The longsword isn't an inferior weapon, though; it's as effective (in the abstract) as a battle axe or warhammer.
No, it isn't. Or rather, it is when you are fighting unarmored peasants. But when fighting more heavily armed foes (anyone with metal armor) it is inferior. Or in D&D terms, other one haded weapons do the same damage but also have special abilities or are lighter. In both cases on the battlefield people would choose other weapons over the longsword when given the choice.







