There is simply some sort of weaponstat/mechanic/attribute missing.
Right now a greatsword is as agile and wieldy as a dagger. There is no stat that makes larger weapons really more cumbersome than small weapons. The only advantage of small weapons right now is a more attackspeed, which however is negated by the sheer damage, range and hiltslash capabilities of larger weapons in the most cases anyway, especially greatswords. Im not saying there are no great 1h users but there are definitly too many bad 2h users getting easy kills.
If you ask me 1h should deal damage in early animation stages instead of 2h. It would only make sense from a balance and a realism point of view. A light, onehand weapon should need less space to accelerate. Also 2h would actually have to watch out for their sweetspots instead of sideswing spamming and killing enemies approaching from behind without even noticing while spinning like a helicopter.
2h "hero" class should only be effective when used by real heros.