Then you'd probably LIKE teaming with my teleporting ninja MM with Oppressive Gloom; he Team Teleports into the most central mob I can see, then Folds everything else in range to him. Brings the melee to the melee players, stuns everything off the squishies. Pets help with the killing.
As with many powers, there can be right and wrong ways to use them, particularly when on a team.
Edit: Granted, I also ask teams how/if they even want me to do this sort of thing. Many seem to find it genuinely helpful, but I'm still perfectly fine with the answer being "No".