I think that polearms with a length greater than 180 should get a unique stab animation. I don't want these weapons to be nerfed because they're already pretty underused outside of strategus as is; however, they're a little bit silly. I was watching goldilocks on the duel server with a long spear. He would look straight up, thrust, and then look down. Whoever was standing immediately in front of him would get hit for full damage. I know warband physics are far from perfect, but I think we could fix it with an animation change, and a "deadzone" change.
1. Animation. The current polearm thrust animation involves gripping two points on the shaft and then outstretching your arms until they are completely straight. There are two ways for this to be done: one, the hands are held close enough together that the arms can be extended fully. Two, the hand closer to the point of the weapon slides down the shaft as the weapon is thrust. The second one allows for more reach but less stability, the first is the opposite. Judging by the minimal change in the distance between the hands during a polearm thrust, I guess that the first option is closer than the second one to how polearms are thrust in warband. Perhaps weapons with a reach greater than 180 should get the second thrust type, where the hand slides down the shaft as the weapon is thrust. This could grant some bonus reach (around 20, maybe?).
2. Deadzone. When thrusting, you can turn to your side and then turn back after releasing the thrust. I believe this gives more damage from speed bonus. This proceeds the animation enough so that the weapon will not glance. I think that polearms with a length greater than 180 should be limited to a small region (or deadzone) when thrusted. This means that when you thrust, you can only turn so far (in any direction) and not make physically impossible speed bonuses for yourself.
These suggestions are more so for pikes and long spears than the other weapons, like ranseur and long awlpike, but it could work with them as well. Please reply with your feedback/ideas for longer polearms.