I think you guys have your frustrations correct, but solutions in the wrong place. There is nothing wrong with horses bumping, the riders weapons are just too Arcady and have a huge advantage that can be spammed over and over with no consequence.
I am working on expanding on realistic weapons collision that has all polearms breakable. And couche lance, stab lance, swung pole arms stick to the victim on hit as it was a throwing spear if there is enough momentum difference between victim and attacker.
It works quite well as it makes it more like a throwing spear, high reward singe use weapon. Then forces the rider to switch to secondary, one handed weapons which currently no one uses ever in multiplayer. Will post a gif later