Speaking about couched lance being "OP" and realism, what about the fact that 60% of players can jump-teleport 3 meters to the side, dodging any couched lance. I know particle tunneling is a very important part of quantum physics, but it shouldn't apply on entire humans. Couched lance is much much much more than pressing x and charging someone. Try that, and you'll either die or miss.
Footmen are extremely agile and impredictible from a horseman perspective. Couched lance is a bit like trying to hit a powerboat with a supertanker.
Couched lance with or without shield against a ranged is a oneshot vs oneshot situation. The ranged hits the horse or the rider, the rider dies. In the opposite case, the ranged dies if the couched lance didn't mysteriously go through (that can happen to throwing projectiles too, or when it doesn't go straight).
I think nearly all couched lance kills are ninja-cav kills. As turning ninja is the only way a cav can more or less safely approach a ranged unit and couched lance is the safest way to kill that ranged (lance pokes don't always onehit men wearing tunics), no wonder it looks OP. It seems "OP" means "able to kill me" for some people.