The overall RANGE of ancients figures is indeed smaller than that available in larger scales. That is essentially a reflection of the number of active manufacturers working in 6mm, 15mm and 28mm. In the larger scales the coverage of core subjects such as Romans, Greeks and Persians is comprehensive by dint of the number of overlapping coverage of the same armies. As a result newer and smaller companies resort to producing more esoteric and specialist subjects thus increasing the overall breadth of coverage. Personally I suspect that the 80/20 rule kicks in and that the vast number of sales are still in the core subjects and ranges.
6mm, on the other hand had just the four companies with Ancients ranges, and to be honest, I think that between us we make a pretty good job of coverage – you can get most things are pretty good proxies right through from Bronze age to late medieval armies.
The other thing about 6mm is that it is ideal for 'conversion by paintbrush' without the need for physical alterations or modelling work. So, yes, far fewer specific variants available, but still a very comprehensive coverage.
As for posing, this is a separate issue to the OP, and I can only answer on behalf of Baccus:
We do provide multi poses and dress variants where it is appropriate. For example, there are only two types of Late Republican legionary but 16 basic Celtic warband types, and if you want to get picky NINETY SIX variants of German infantry!
While I agree that our GNW Swedes are lacking a little aggression, (which is something I will address in the very near futre), all of the horse and musket poses are chosen with care. Put simply, period drill required every soldier in a battalion to be doing the right thing at the right time in full coordination with every other man in the unit. When I see 28mm period 17th/18th C units where every figure is posed differently and looking in odd directions, I am looking at a military disaster in motion! Any sergeant worth his salt would be giving that rabble a very hard time.
Carrying a musket is hard work. Marching with it is hard work. You keep it in a vertical or near vertical pose for as long as possible as that is the most practical and least demanding way of carrying it. You have it levelled for firing for as short a period as possible as it saps your energy. Unit commanders knew this and prior firing systems are predicated on it
I don't do multiple poses as there is no need for them if you are trying to reflect history and practice, and I'm not going to really offer apologies for adopting that policy.