Ok, so you've partly persuaded me that horses really should be an unstoppable force (though I'll still be interested to hear a reply to fodder's suggestion about a wall of shields, so I'm not yet 100% convinced, and I've seen horses at the showjumping refuse running over/through/whatever a hedge or a gate or a pond - none of which were firing at it with muskets).
I'm still somewhat unsure that their higher cost is proportional to their higher power, but they do at least have the inability to attack walls, so that's something, certainly. And the fact that all the gamers don't run off and recruit cavalry and nothing else suggests it can't be too overpowered overall.
The thing that still bugs me though is the CS values.
First off, the horses should, I think, have a higher CS value. Granted, if they're up against walls, then they're useless, and their CS could be assumed to be 0, or close to 0, if against walls. But that's fine, you just work out if the battle has walls, and if it does, you replace whatever CS value they have with the number 0.
And so the CS should be representative of their power in the fields 9because it is not possible to look at the CS, guess what percentage-of-battles-against-walls were used in their calculation, divide by that percentage and come up with a 'fields' CS value for them). I'll concede that one battle is not a good sample, so I'll see if I have more in future that are appropriate to consider for this topic. But based on that one sample, the CS of the cavalry should probably have been double what it actually was.
And then the peasants. Oh joy! I have another battle with peasants on which I can now report. And it's quite a good one for this discussion, though I did forget to put my infantry back to line, but never mind:
Battle:
Attackers: 3 Infantry (box, CS 64)
Defenders: 18 Angry Peasants (line, CS 60)
So here we have a battle between almost equal forces. 60 vs 64.
The 60 Angry Peasants are in line, and the Infantry are in Box. So the Angry Peasants should do a little more damage than the Infantry. And the Infantry should be able to absorb a little more damage without dying than the Angry Peasants. So that should still end up pretty equal.
And the Infantry w/a is 50%/49%, which are very equal, so I'd not expect a particularly strong or weak performance in either attack or defence from them.
Round One
18 Angry Peasants score 5 hits (3 after overkill)
3 Infantry score 25 hits
One peasant dies.
Round Two
17 Angry Peasants score 4 hits (3 after overkill)
3 Infantry score 26 hits
One peasant dies.
Round Three
16 Angry Peasants score 4 hits (3 after overkill)
3 Infantry score 36 hits
Two peasants die.
Round Four
14 Angry Peasants score 3 hits
3 Infantry score 29 hits
One peasant dies, and the remaining peasants retreat.
So... 64 CS vs 60 CS.
The 64 CS do between 25 and 36 hits each round.
The 60 CS do between 4 and 5 hits each round.
And it's not as if the 60 CS have something like 5%/95% weapons/armour, firstly because they didn't manage to withstand the hits on them that well, and secondly because I bet that peasants would be given a flat 50%/50% split by the game code.
So as far as I can see, and I'm now up to 2 sample battles, the CS value of peasants is greatly overstated. They should have been about 9 CS, not 60 CS.