Dismounted cavalry players ARE at a disadvantage when compared to normal infantry. They have to have fairly high agility, and use several skill points for riding. In that respect, their ability in a melee is similar to that of an archer. They can hold their own if they're skilled, but they'll never be as capable on foot as a pure melee character.
Honestly, I think that the heavy lance is fine as it is. Its damage, length, and speed are all very well balanced, and the ability to use a sword+shield or 2-handed weapon as backup is perfectly fine.
Rather than lances, I think that the heavy horses are what need a nerf. Their use is supposed to be restricted by their high upkeep, but cRPG has many long time players with deep pockets, to whom upkeep is a non-issue. This is bad news for the rest of us, who are forced to endure their extreme resilience and endless bumping. They were kept somewhat in check by the proliferation of long spears and pikes, which could needle them and keep them at bay with rearing - but with the latest patch, they've got free reign. It's almost a futile effort trying to fight them at this point; you can swing at them and take a fraction of their health at the risk of being speared, or you can block and be trampled to death by bump after bump after bump - and that's only in a 1v1. A player on a heavy horse with heavy armor and a heavy shield is able to charge through groups of embattled enemies with impunity, knocking them down like a bunch of helpless medieval bowling pins. I understand that bumping is a large part of what makes heavy cavalry useful, but IMO it's gotten completely out of hand.