Those missed registers aren't really a problem since if your build is not fucked up you can easily oneshot the poor guy that stopped you with a short weapon. A thrust of your one handed lance in his head when you don't even move, although it won't with any other weapon, even on foot. I don't know why heavy lances are so powerful when the lancer doesn't even move.
I think your perception is flawed because you didn't completely adapted to the slower speed.
This is why I only invest 4 points into riding instead of 6 and dropped the heavy lance and any polearm proficiency. One handers and two handers are the way to go from horseback now. Granted I get killed a lot, but if you play it right, it's great fun and very effective.
Trust me, it's the other way around. 1h cav has allmost no chances against a lancer and infantry also is more difficult to kill. Furthermore, you can't do couched sword
As polearms already are the way to go on foot (GLA, LHB, Glaive epic spamming builds), they are really the best choice on horse too. Just watch Torben or Tommy stacking kills then watch a 1h cav that gets the same amount. Hell, you won't even likely find one.