What kind of polearms would fit better besides BEC?
Anything on the shorter side that is fast and spammy (not unbalanced). So the bec, polehammer, the plancion should be good (never used it), the long maul is good but unfortunately not available to everyone (dunno why they raised its difficulty with the high level patch, but failed to lower it after levels were lowered). You'll want a good assortment of 2d poles, some longer ones like the corseque or ashwood (in case there are hoplites), and shorter ones like the battlefork or awlpike since plenty of the fighting is close quarters on the walls, in gatehouses, etc., although you obviously won't need too many 2d poles. Then even cheaper weapons like the boar spear or short spear can do work.
Tl;dr: Short and spammy stuff with as high pierce or blunt damage as possible, gotta be able to let your polearms duel as opposed to only play support, just in case they're caught on their own. Even having the option for a few unbalanced weps wouldn't hurt, so long as they hit hard, i.e. the long morningstar.