Removing couch lance would weaken cav heavily. Couch lance is just part of the game as chamber for example is. I like having it in the game. You also have to notice that it is usually easy to avoid being couched unless you either don't care or get attacked from behind (in that casees it's your own fault).
The bump couch lance doesn't happen often so why remove it (or weaken it)?
If that would be removed something else should be heavily buffed for cav, e.g not let the horse ever get 1/2hit again just when aiming at the legs (which is awful anyway).
And Leshma, just because you get some kills of unaware players, doesnt mean the class is overpowered. It's the same with crossbows on the ground, you can pick them up and do headshots.. oh just 1 wpf? LETS nerf crossbows! ;)