Cav IS OP. I think the reason some of you don't notice it is that you just charge once.

I use general cav, and I pretty much destroy anything in the way. As soon as the cav meets the enemy, I tell them to withdraw. They do so immediately, and I lose maybe one guy. In the meantime, my ubercharge kills like 10% of their unit (it's easy to charge slow inf in the flanks). Rinse, repeat. The only thing that counters my cav is enemy cav.

I suggest that cav should not be able to withdraw as easily. Once a cav charges, it should get bogged down almost immediately, and if you withdraw, you should lose a significant amount of your unit. Then you would have to be much more careful with your cav charges, instead of running them around like a panzer.