Don't boost horse upkeep. You asshole, I want to actually ride the fucking thing, which is hard enough now. An infantryman can use very nice equipment without suffering retarded money rape. Cav should be able to do the same, too.
Destrier, Courser, and Arabian are the "decent" horses. Things other than those suck, and things more than those are OP. Well, they would be if their legs weren't gigantic self-destruct buttons.
None of this will matter when I sell a loompoint this gen, finally. A few more weeks of play, then money will never matter again. Which makes sense. I mean, why shouldn't I be able to all but ignore a game "balancing" mechanic?
-----------------------------------------------------
And, as I've said before, cavalry's number one counters in cRPG are teamwork and awareness. An aware player can avoid a charging horse, or attack it. A friendly pikeman that is made aware of the presence of a flanking enemy cavalryman via effective communication is able to fuck up horses.
Awareness is mostly up to the player, as he/she is responsible for listening/looking for cav. Though, the way horse-hooves sound in game can be a little off. Really, I think it's ok in cRPG.
As Bryggan points out, however, the lack of in-game VOIP means that infantry can't communicate fast enough. This is the biggest issue with regards too communication, really. Either have a cRPG public TS (fuck Ventrilo) that anyone can join, or somehow put VOIP into the actual game using powerful development magics.
Or nerf cav into oblivion. Fuck it, if you can't fix it right, you just gotta fix it dead.