If Mence is Uber, then it will be by the Support Clause, I think. Offense: needs decent support; Defense: surely, you jest ("you" as in, anyone who brings it up).So thats THREE, coun't 'em, THREE other pokemon that are in this fictional team for the sole purpose of supporting a mence sweep plus the mence itself and the player then only has two other slots, this mence isn't going to have very good coverage (seeing as it apparently has substitute, dragon dance and outrage - it gets to pick one other attacking move for coverage) so those other two slots would almost certainly be backup sweepers, probably something with priority to finish off what mence started.
As for support, well, can Mence blow a big enough hole in teams to count as Uber?
Anyway:
The current metagame is weak to kamikazes. CB Selfdestruct Snorlax, Metagross lead with Explosion, etc. I think blowing up a lot might be a good strategy to blow holes in teams - certainly better than it was for me in Standard.