After playing for few hours with cav and against it on foot with my reg on 92nd server, it was clear as a bell that cavalry is seriously underpowered.
The increased accuracy of muskets, being a big target and ridiculously low speed of horses means that at close to mid range infantry are guaranteed to hit and cavalryman without luck or difficulty.
Charging at infantry which has minimum self awareness has became impossible, as bayonets have such a huge adv. over horses. One stab kills or stops you(which means death anyways) and your horse, and sabre has nowhere near its reach to be able to counter it in any way. People that write that you can still attack from behind must've played with newbies who didn't look behind them or were deaf enough not to hear hooves of the horses. Cuirassiers should be able to charge into the enemy formation and wreak havoc in there, but half of them gets shot before they get due to their move speed being little more that art. horse and the rest is just stomped by bayonets.
While it takes 1-2 bayonet hits to kill anybody, with sabre if you are not moving at full speed it takes about 3 or 4, and even at full speed it isn't guaranteed kill.
Russian lancers have no ability whatsoever to block, and even regular lances have become useless, as it is so easy to kill them with infantry. Their charge should massacre inf., but it works the other way around.
The only viable way to play cav. right now is to go with dragoons, use harass and retreat tactic and never engage in a melee with infantry.
And cavalry is meant to be stronger in hand to hand combat than infantry, as it was in reality. That's why there are limits on the number of them, event though right now they are pointless.