Well since we can't use the UFC standards by weight size, then it should be broken up into special power and weapon usage.

For instant, opponents using only weapons such as Katanas, Swords, ect. that have no special powers should be characterize as Lightweight division.

Those who need no weapons and who has powers such as Ki blasts, elemental powers, etc. should be categorized in the Heavyweight division. For example: Characters from Dragonball Z (Goku. Vegeta, Gohan, Trunks, Goten, Krillen, Piccolo).

But then you have to choose what group characters such as Dante (Devil May Cry) would fit into. He uses both weapons as well as special powers he gets from being a half-demon. If he's chosen to be considered a heavyweight, then he wouldn't be able to use weapons at all and visa versa.

That's my two cents worth. ^_^