Lancer cav seem good enough to me. Play smart and you can even get a rouncey to last round after round. I think a single lancer was way too powerful back then, and melee cav can learn a little bit from archers/infantry for sticking closer together or coordinating paths. Cav classes are some of the easiest to do teamwork with on the fly.
I wish there was a way to make cav v cav fights more interesting. If a horse is running away from you, you're lucky to take 20% damage off if you stab them due to speed bonus/not hitting at the optimal point in the animation. That's the only thing I do not like, since everyone just ends up running away from you.
Can't comment on 1h/2h cav since the 1h I use is too short to keep my rouncey safe.