Monks can stun too
And the DC is so low, that even if it was 3, 5, 10% its useless, so stunning fist/blow is unfortunately the only viable use for weighted stuff anymore.
However, keep in mind that now, in Epic, DCs were lowered across the board, but HP was not. So making things Auto-Crit becomes a primary responsability of arcanes. Melees shouldn't worrie too much about it (aside monks, IMO) unless they have nothing better to do. I rather the barb sticks to his strongest weapon than switch to a weighted when an arcane or a monk can do the stunning, personally.