best class for game completion?

Last time I checked the mastery from Beholder was passive, and Beholder itself can't be dispelled. The Polearm glitch is a non issue after the next revamp since it is Buster that has the problem. Dark impale will not suffer from that.
Self SI favors spears since they have a hefty amount of attack compared to the fast polearms, I should think.
The stacking problem is also going moot, Dragon Blood will give STR and Beholders Hex is already stacking with everything.
Not that this makes DrKs the pomegranate, but your points can't build a case.