We could make it so that their are three weight categories for more records

Well first off, there are technically about five weight classifications in sm4sh. Secondly, weight affects a fighter's resistance to knockback. I'm not sure if you might have mistaken weight for how hard a fighter can hit, but making weight categories would be pointless because for a top run in 10 and 100-man smash, you shouldn't be getting thrown around at all.