Most people who think cavalry is imbalanced are totally missing the fact that... cavalry sucks at sieges.
Really, why dont you expect cavs to be slightly overpowered in battlefields (which is quite logically, isn't it?) because infantry is comparingly overpowered in sieges?
The game balance should include the whole thing, not just battles or just sieges. And from that point of view the game seems quite balanced to me.
PS: turned cav this generation and I don't think it is "easymode", my k/d rate is pretty much the same as before, being an infantry.