Ok, Flashman, I'll bite, you asked, so I'll answer.
First off, Game of Thrones has had in the past amazing cinematography and displayed a fantastic sense of action in major battle scenes. They've previously shown night battles really well, even when they had a more restrictive budget or other production limitations they had to deal with. The assault by the wildlings on Castle Black comes to mind, which was entirely at night. I absolutely loved that episode and was at the edge of my seat throughout. My anger at last night's episode isn't as a hater, but as a fan who was very disappointed with what should have been gold being very much brought down by bad cinematography. There were moments of brilliance in the episode, but overall I was very disappointed. Since the director of last night's episode, Miguel Sapochnik was also the director of Hardhome, one of the best battle sequences of the entire series, I'm not sure why they made the decisions they made from a production standpoint, but I see the siege at Winterfell as a lost opportunity in a series I really enjoy.
First, I'd start in the previous episode. The mood the show was trying to relate in last night's episode was chaos and overwhelming despair. The best way to capture that is to start by getting the viewer's sucked in before the battle even started. During the episode prior, which had scenes I really enjoyed, but overall I found to be really slow, I would have had a scene where a more specific plan was revealed- not super detailed, as this isn't a tactics lesson- it's a fantasy television series, but enough so viewers are invested and to reinforce to viewers that Jon and Dany (or at least someone) has a plan and that everyone is rallied around that plan and has some measure of hope they might survive. Even if they all really believe they are going to die, this is important. The actual plan doesn't have to make tactical sense to wargamer fans who will nitpick it to death- but rather to draw viewers in and set up expectations that can come crashing down later.
This would be something like- Ok, Grey Worm is here and he will defend the main gate. Brienne is going to lead the Stark Forces on this flank. Her job is to hold the flank and channel the enemy into Grey Worm's line where they will grind them down- hammer and anvil. Jorah will lead the Dothraki cavalry, and they will wait until the opportune moment for Ser Jorah to call the charge. This will break the momentum of the dead and they will be a reserve if a force swings around on the castle from another direction, but it is key they are held in reserve until the right moment (and it is key that this is made clear to the viewers for reasons you will see below).
Meanwhile, the trebuchets will pour in literal fire to burn the undead from behind the defensive ditch that will hold back the dead from the walls. Meanwhile, defenders from the wall lead by Arya will pour in fire on the approaching enemy and Jon and Dany will provide air support with burning fire. Hopefully, we keep grinding them down before the walls are breached.
If things go bad, we fall back behind the ditch with Brienne and Grey Worm falling back in ranks and from there people funnel into the main gate to hold the walls. Our overall job is to stop the enemy long enough that the Night King has to appear, and when he does, we attack him from multiple avenues. Jon will directly challenge and Dany will attempt to strike from the side while everyone else looks for an opportunity to strike him down. If only one of them survives, it is paramount they kill the Night King.
It's important to relate a plan and an endgame so that viewers expectations are set. The reason to do this is to invest the viewer with their favorite characters and what they are expected to be doing, and to prepare the way to make the viewers feel the chaos and desperation when we start pulling the rug out from under the defenders.
Everyone can then finish up that episode pretty much as they talking about how they are going to die, but saying that at least under Jon and Dany's leadership they feel they have a chance, and better to die for a chance than to just wait to die.
Now, we get to last night's episode. We already established that the dead were here at the end of the previous episode, so the whole first 15 minutes of people marching into darkness was pointless. Also, in the previous episode, the last shot is of the army of the dead facing Winterfell and was quite well lit, so going to the weirdly dark look in this episode is jarring. The top Game of Thrones Twitter trend for the night was about the episode being too dark, so clearly it was an issue on some level.
You definitely want the viewer to feel the darkness and confusion of the people in the battle, but if the viewer can't see anything and is confused themselves, it doesn't ramp up the tension, it simply frustrates the viewer.
So, I would have had the armies all set up and waiting at the start, and leaders chiding their forces to 'remember the plan' that we established in the previous episode, and 'if we stick to the plan, we might just live through this night.' We don't see the dead, but we do see the black wall of night at the limit of their vision. We do hear the dead, however. Audio was not used to ratchet tension in last night's episode, and that was inexplicable. In my version, we hear marching feet- lots of them. It sounds like all the hordes of the dead that ever were are coming to Winterfell.
We cut to shots of nervous soldiers and leaders starting to worry. The sound is terrifying and un-ending- but we still can't see them. Finally, someone, probably Jon, who hasn't taken off yet on his Dragon, calls for the Trebuchets to fire.
We have a long shot of flaming balls going off into the distance. They go for several seconds, hypnotically capturing everyone's attention until they finally, mercifully, hit the ground and light up a huge set of fires landing just in front of and revealing the army of the dead- massive in numbers and wholly disheartening to the defenders. We see near panic on the faces of everyone as the enormity of the enemy they face stands against them.
At this moment, we see the scene of Melissandre showing up pretty much as it happened. This gives hope to the defenders. However, the Dothraki are chafing at just sitting there. They see the enemy, they want to charge. Ser Jorah is telling them to hold the line and doing his best to hold them back. We cut to Brienne, telling Jaime 'those fools are going to charge, if they do, they'll doom us all.' Then we cut back to the Dothraki…first one, and then another start to charge, causing a chain reaction and Ser Jorah has no choice but to join along. They ride headlong, yelling Dothraki war cries and the horsemen crash headlong into the undead. Only then do the lights from the trebuchets start to go out, and then the lights of the flaming swords until everything is pitch black, accompanied by deathly silence.
From a lighting standpoint, I'd make the distance pitch black, but light everything around the castle much brighter than they did to draw a clear line between the false safety of the light versus the unknown of the darkness beyond. The darkness should be a border that creeps ever closer throughout the battle to reinforce visually the loss of hope and to heighten the fear of the coming darkness.
We see everyone back at Winterfell's faces drop. Clearly this is terrifying and demoralizing. The plan is already starting to crumble.
We now hear the sound of a rumble that grows louder and louder as first one riderless horse appears within view of the defenders (and viewers), followed by another and another. Ser Jorah and a few stragglers come riding into view and head back toward safety. They are a handful of what was once a mighty horde. The defenders gasp.
Jon calls for calm, and nods to Dany. Only now do they mount their dragons and take off in an effort to grant hope. They light up the ground in front of the defenders as the enemy finally begins it's charge.
Everyone girds up, and it appears that despite the loss of the Dothraki, the rest is going to plan. Brienne herds the enemy into the waiting forces of Grey Worm and it becomes a grindstone. Bodies pile up and everyone begins to hope that this will work. Jon and Dany are burning up all the zombies they can and they even exchange a smile as they work as a coordinated team.
Now we reveal the Night King from the other side of the Castle as he orders an assault of more undead directly at the walls around the Gods wood. A horde of undead rush at the castle from that quarter and get close- too close before they are noticed and a cry of alarm goes up.
The grindstone of Grey Worm and Brienne are out of position and they realize that everything until now was a diversion and a feint. Dany stays to burn the force in the front of the Castle as Jon heads off to face the new threat and buy time.
Likewise, Brienne orders Jaime to take half her force to fight the new enemy. It's clear that everyone is now out of position and the plan is out the window. There is no choice now but to withdraw everyone to within the trench, light it, and get everyone back into the castle as Jaime delays the enemy. (We the viewers understand this from the plan outline the previous episode and are invested- and worried, because things are looking desparate)
There is a fighting retreat to the walls as Arya and the archers pick off undead from the battlements. We still have the desperate scene to light the trench, but now with the added tension of Jaime attempting to fight off a much larger force long enough for the trench to be lit. The trebuchets are turned as well and pour on fire, some of it landing among Jaime and his men.
As the lines collapse inward toward the Castle, and the retreat working inward, Brienne has the chance now to run to aid Jaime and just as it looks like Jaime will be overwhelmed, Brienne comes to the rescue and pulls him back toward the trench. The two cross it just before it lights up, temporarily halting the undead as Arya and the archers pour in murderous fire. For the moment, both of the undead forces assaulting the castle are held back.
Jon has a duel with the Night King and his Dragon, darting back and forth and each doing damage to the other. The cool 'up into the clouds' scene remains, but with Jon and the Night King giving and taking. Suddenly, the Night King gains the upper hand, causing Jon and his dragon to crash toward the ground. Jon is under his dragon hanging on for dear life and it looks like he will be crushed just as Dany's dragon slams into the Night King's, and Jon and his dragon make a ragged retreat, visibly struggling to gain altitude.
The Night King does his magic thing to call snow and darkness around him and escape into the night. The dead now do their thing where they throw themselves into the trenches as the forces of our intrepid heroes retreat back into the gates. We then get the assaulting the walls scene largely as it was last night (but with better lighting), and with the defenders lined up to repel them rather than only the manning the walls. It is important that the darkness now encroaches all the way up to the walls of Winterfell. This reinforces the desperation and impending doom. The defenders can barely see beyond the walls now, but within Winterfell, everything is well lit by fire so that the viewers get what is going on.
Jon and Dany can't use their dragons against the walls, or they risk killing their own armies, so they pour fire on into the darkness just beyond the walls desperately against the onrushing forces. We show them making a great but increasingly harried team. The dead keep coming, though, and the dragons visibly tire, their throats becoming hoarse and their fire beginning to lose it's power.
The first dead are now breaching the walls, and we hear pounding against the gates from thousands of dead fists. We then get the giant scene largely as it was (but well lit), a cloud of darkness making its way just inside the gate from which multitudes of dead rush in. However, the darkness at the gate is only to reinforce the sense of the darkness breaking in as if it were itself a physical presence and and enemy combatant. The rest of the scenes remain lit by the fires of Winterfell.
Jon and Dany, their dragons nearly spent have a brief shouted conversation trying to come up with a new plan. They are visibly on the brink of panic and hesitating. At that moment, Jon is again slammed into the darkness by the Night King on his dragon. The two dragons savage each other and this time the two crash to the ground (somewhat like last night).
We have the same scenes of desperation as Jon attempts to confront the Night King, but he does his undead thing and everyone starts getting up, just like last night, and all looks lost. That scene plays out largely the same, but Dany comes to the ground after saving Jon because her dragon is spent. There is a brief lull as Dany begs Jon to chase the Night King down. We see the dead now approaching, and Dany desperately trying to coax her dragon into the air before the dead can get to it, but to no avail. We then have the same scene of the undead savagely attacking her dragon, but with Dany screaming for the dragon to take off, and finally the dragon throwing her off and then ambling clumsily along the ground away from her to save her from the undead. The dragon trundles off into the darkness, its fate unknown, leaving Dany by herself until Ser Jorah arrives to have the same desperate fight.
I haven't mentioned Arya, as her scenes from here basically play out the same up until her and the Hound are holed up in the room with Melisandre. The only change I would have made up to now is to better light the scene in the (library?) where she was trying to evade the undead. I honestly couldn't make out anything happening in that scene. It was somewhat like the scene with the raptors in the original Jurassic Park closing in on the children in the kitchen, but in that movie, they used viewer knowledge to ratchet up tension. This just felt like a muddy dark mess. With better lighting and relying on strong camera work, the scene would have been much more tense.
So back to Melisandre. She has the scene with Arya, but Arya pointing out they were now trapped in the room with no way out (this really bugged me in that scene- how did Arya get out?). Melissandre then tells the Hound to open the door (and he tells her off in classic Hound style) before Arya puts her hand on his, looks him in the eye and tell him to open the door. He pauses and then does so, at which point Melisandre uses the last of her fire to burn the undead away (and immolating herself in the process), clearing a path for Arya to escape (and giving us a much more exciting, and meaningful death for her than the stupid scene of her wandering into the snow and just falling over). She would immolate entirely, burning up. (As an aside, as she burned up, I would have had her face change to Syrio Forel's and then change again to become the head of the Faceless Men as he says "valar morghulis" and then cut to Arya running through the now empty halls and whispering as if she were responding to him, even though, by now, she is long gone, 'valar dohaeris.')
The rest of the show would play out pretty much as it did with some notable exceptions. Jon just about catches up to the Night King when the undead dragon slams down between them in the courtyard, preventing him from reaching his goal. I'd have had Jon make several attempts to proceed, and even stab the dragon a few times, but the dragon stopping him regardless. The reason for this is so that Jon doesn't look so hapless. He still fails, but he at least is trying very hard, and hurting the dragon, even if he isn't defeating it.
Down in the catacombs, I would have made it clearer that the undead were the bodies in the crypt emerging (my wife was confused- she thought the undead from up above had dug down- it wasn't clear). Hell, if I could have, I would have had the headless body of Sean Bean rise up as well. Rather than everyone cowering and hiding, I would have had Tyrion and Sansa standing shoulder to…well, stomach? (He is rather short) as they try to stop the onrushing dead from killing the innocents stuck in the crypt now filed with enemies as they fall back further and further into a smaller and smaller space. They should have both had a chance to kill undead and look actively heroic.
The scene with Bran and Theon was probably the best scene in the episode (and the best lit- is there a correlation here?). I wouldn't change it (though I would have had Bran do something, or at least indicate he was doing something useful. His whole "I'm leaving now" scene seemed to have no point). I'd have him having his ravens make attacks just at the nick of time to save people in the episode so that it appeared that he was engaged and not just siting there, or at least spying on the Night King.
Back to the scene in the Godswood- Theon dies as he did- heroically, and Bran is all alone. Bran speaks to the Night King. Hell, I would have had the Night King speak. He could have revealed something- anything, to pay off 8 seasons of build up. It wouldn't need to be much, but some kind of reveal to explain what the whole point of it all was. As it was, he spent 8 seasons building up to…nothing.
He approaches Bran…and we see Arya getting into position to make her leap. Not a long scene- just a second or two of her dropping down behind a tree, or sneaking up behind one of the undead- not much, but this is critical, I feel. Her leap at the Night King felt like Deus Ex Machina rather than the pay off to all of her training and a storyline that had been building to this. By showing her preparing to strike, it shows her as a cunning and able warrior instead of a surprise plot device. Critically, this sets up the expectation that Arya is going to kill the Night King, but makes the moment where the Night King turns to grab her that much more tense as we expected her to win, but then he stops here. It's one last punch in the gut before she manages her knife trick.
Back outside, Jon is desperate to get past the dragon and makes one last all or nothing charge at the dragon. The dragon is about to breathe fire, and it is clear Jon is about to die, but at least he's leaping for all he's worth at the dragon much as Arya is leaping for all she is worth at the Night King. I'd mirror these actions somewhat to make them both seem like able and capable warriors in desperate situations and to mirror the actions of the two cousins (since we now know that they are cousins).
Arya is successful, the undead all fall, the rest plays out as it did (with Mellisandre already dead).
I feel this would have paid off the 8 seasons of buildup in a much better fashion, and build upon the great ideas we did see in a way that fans would be invested in. As it was, we got a muddy mess and a disappointment rather the kind of 'did you see that?' event that only comes along once in a very long while (and what was the hall mark of this series up until now).