For some time now, i was under the impression that polearms got more easily blocked/interrupted by obstacles than twohanders.
According to the game mechanic megathread the animation-modifiers of a right to left swing are:
Twohand = +13
2h Polearm = -2
A Heavy Bastard Sword (105) and a Bec De Corbin (120) should then be of equal length.
I tested the following on the duel server:
I tried to hit a non-moving shielder with both weapons and without moving, while keeping the "view outfit" key pressed to prevent different attack angles.
I found a position where the Heavy Bastard Sword hit the shield (standing at my right side) and the Bec De Corbin did not.
:
The weapons should then be at least of the same length.
Next i tried hitting a stone wall at the same position the shield was before.
When the attack of the Bec got interrupted by the wall, the Heavy Bastard Sword's attack was not.
It might be a only related to one of those two weapons (i did not investigate it further) and i am only assuming this is a difference with weapon classes.
Anyway. i just wanted to point it out.