Brigade orders when they are successful are fun— they move the battle along quickly.
Brigade orders when they fail are abysmal… yet the game moves along even more quickly, because now it's the other player's turn!
I like lots of units on the board, so a one order per character rule makes that untenable— the odds mean the bulk of an army won't ever move in any given turn. The brigade system allows for a greater probability of the entire army moving, or at least a significant portion.
Right now I often play a doubled-sized Battle of Five Armies with 150+ stands on the board— 32 units of goblins/wargs, plus 6 goblin characters vs. 19 "Free Folk" units and 5 hero characters. I've run this at NashCon for 3 years. Takes up a single 4-hour slot, same as any other game, and every time it's reached a decisive and clear conclusion, with almost all units of both sides becoming involved in the fight. (I think maybe once a unit of goblins didn't move close enough to be engaged, but that appears to have been a fluke.)
My total investment in the above is less than $100 USD, as I got the original set on clearance (half off) and the second set from a private sale/trade at roughly the same value. Paint & glue costs were minimal.
I also have some standard Warmaster armies— Orcs & Goblins, Dwarves, also less than $100 USD (again, another clearance sale). And in a trade, two massive armies of Empire and Chaos forces that I've yet to paint or play. Again, way less than $50 USD in trade costs to me.
And I've filled out my Bo5A and O&G and D forces with Kallistra and Copplestone 10mm fantasy not-LotR sets, which I consider very reasonable— another $100 USD?
All of this is over twenty years or so, so it's not like it came in one big purchase.
So, yeah, I think Warmaster as is can be quite reasonable in cost. Plenty of 10mm and 6mm or even 15mm manufacturers out there which can fill the bill for not much dosh. (Warmaster is ostensibly 10mm, but really almost any smaller scale will work.)