@PualTa: In RTW they had spears instead of lances, same thing, just a smaller version, theirs no intrinsic problem because of lance as they're just bigger versions of the spears.
Actually a lance is significantly different from a spear. It has much more mass, and has no real utility outside of a charge. Lances developed AFTER stirrups for a reason, there wasn't any use for them until a rider could anchor himself to a horse better. It's like comparing an assault rifle to an MG... sure, they both spray bullets, but one is a multi tasker while the other is highly specialized to perform one task MUCH better.