What if they just made 0 wpf couching have a chance to snap the lance off and back into the face of the user?
Same idea would of course go for crossbow. Maybe because you have no wpf in xbow, you load the bolt backwards, for some reason think that they need gun powder, and then just blow your face off.
On a serious note, elaborating on my earlier suggestion: 100 wpf in polearms, the chance to lose the lance would be 10% on light armored opponents, 15% on medium armored opponents, and 20% on heavies. 150 wpf would shift the chances to 5%, 10%, and 15%.
That'd give -dedicated- lancers roughly:
-1 in 20 chance of losing the lance to light armor. Occaisionally it'd be an unlucky jip but the lancer would also go entire maps of peasant couching without losing the lance.
-1 in 10 chance of losing the lance to medium armor. Again, you could end up going an entire map without losing the lance. The lance risk would be greater, but you would also still have very good chances for killing multiple medium infantry.
-3 in 20 chance of losing the lance to heavy armor. Still not all that bad when you consider how valuable it can be for your team to take out heavy infantry. And just a bit less than 1 in 5 chance. Which means sometimes you would still be able to couch 5 or more heavies.
This would add value judgement to decisions about who to attack (armor class) and how(stab vs couch). Hybrid lancers would still be able to couch, but the more they couch the more likely they would have to rely on their other skills. And of course those chances are just for the purposes of illustration.