Without some armor toggles or controls, this AT would suffer greatly while in melee, survival-wise.
You could do something like this, (I'm just using a mix of empathy and invulnerability as an example, here):
1. Healing Aura
2. Temp Invulnerability
3. Unyielding
4. Resurrect
5. Clear Mind
6. Fortitude
7. Recovery Aura
8. Regeneration Aura
9. Adrenalin Boost
You'd likely need to swap in more Invulnerability powers or adjust the specific numbers/durations/etc until you find a good balance, but it's doable. For instance, maybe you could turn clear mind and fortitude into toggles that benefit the user and their allies in a small radius, instead of including armor powers at all. Sets like radiation could be turned into user-centered AoEs that debuff nearby enemies, thus increasing that character's survivability that way.
As for a class ability - what about some sort of "tagging" system, where enemies suffer a debuff, and you gain a buff for every such tagged enemy within 15' or so...