As I recall, the original justification for Mind not having a pet was that with Confuse powers (both single target and area) we were going to make our own "pets" from the local mobs. That would be okay, if I got xp for stuff my "pets" killed (like other controllers get for their pet kills), or if my "pet summon" didn't require a to-hit roll (like other controllers can auto-summon pets), or at least if Confuse triggered Containment.
But then we got Dominators, with a better inherent and more damage (ultimately, the name of the game is damage). And then we got Plant, with all the control and confuse of Mind plus pets. And then too many things became more mez-resistant, effectively cutting controller damage.
Another problem is the mission design, with so many missions that are de-facto kill-all. Almost like a stalker, Mind is a scalpel in a game that encourages hammers.
All that being said, I've mained a mind/kin controller since Issue 6, and nothing else holds my attention like it. Kin does round off some of the rough edges of Mind, though I respec'ed out of Repel and TK at the first opportunities and never looked back.