Statesmen, the problem with higher level heroes fighting at such incredible levels of power largely comes down to two factors: crazy AE damage and bubbles.
Whenever a TF forms, the groups assembles anyone they can. Only prime requisites for fighting +3 or +4 mobs is damage from blasters and a force field defender to block all incoming blows. Nothing works so effective as that combination. Without the AE blaster/scrapper type, the damage slows to a crawl, people give up. Without the bubbles, people die, people give up.
Please try to bring those two elements in line with the rest of the powers available to heroes. Currently, healing/single target attacks/debuffs not maxing damage aren't the problem.
However, if you do drop the over powered super powers to an acceptable level, please make sure not to slow down the exp to a crawl. Most people hate those 8 person groups without AE damage/bubbles because exp goes backwards if anything. Much risk, very very little reward.