I'm pretty sure the sword I held was a Bastard Sword, or Hand-and-a-Half. It was definitely at least 15...
I guess I'll just google it. But I don't think I'll change the weights, just add some more fluff about how the legendary swords are heavier, or sometimes liter then normal due to the magic within them.
Grimsage, you didn't say what the sword looks like.
Magic has weight... I like it. Could be a good way to balance things... Buffs have weight, so the wizard can't stack to many, or he can't move... I think you're on to something there.
There is no 'overkill.' There is only 'open fire' and 'time to reload.'