I guess I am missing something in the equation.

I would think that the reason for playing against various factions was to face a different tactical challenge.

If all of those factions are basically the same, where is the verity?

But if you look at it with historically correct units there is wide variance. If the Prussians are firing 5 shot a minute with 35 or 40% accuracy you are not going to stand and duel when your troops are firing 3 shots a minute even if they have 65% accuracy. Of course the Prussians took longer to train and so would cost considerably more to acquire.

The wider the difference in units the wider the verity of tactics needed. If this leads to some factions being less popular with some people it is only natural. Some troops took much more thought and preparation to be employed effectively. But that is a part of the challenge.