one of the advantages of swords against polearms that i see is that once you get inside the range of effective polearm swings the polearm user would have a much harder time using this weapon at close ranges. Thus their effectiveness in large groups as they keep enemies off each other and within optimal range.
Secondly, I have no idea how much a halberd would weigh but i would guess around the same as a large 2h, yet i imagine the weight would be concentrated towards the end yes? This would mean a hit would do a great deal of damage, yet it would also be more tiring to use than a sword.
Also, i have read about varying lengths of these weapons, but how long would you guys say it is (i'd guess about the size of the person using it).
my point is, anything that extends to behind your body becomes harder and slower to use if you plan on swinging to the sides, and once your swing is complete it seems to me that a swing from a long polearm would leave you open to an attack from the enemy. Ingame the staff of most polearms travels readily through the ground or your body, but in real life its not that easy.
I know we are getting dragged into realism discussion here, but this is actually interesting for me at work