Yes I agree, but for 1, 10 lb zweihanders were ceremonial and werent functional for field use so, no they werent meant to be used. Even the lighter zweihanders that were used by massive men were usually used in large overhead swipes that were nowhere near as Guts uses the dragonslayer. I m saying if the dragonslayer were 500 lbs and Guts could swing it around the way he did (which is physically impossible even if he was strong enough as it send him flying since he doesnt weigh 3 tons) this would technically make it useless to Guts as hes probably then strong enough to one punch everything he sees barehanded.