Given the changes in 3.2, I personally can't see any major changes that either wouldn't overpower AST or ruin the flavor.

Some complain about how random the cards are, but personally I find myself very rarely in a position where the card I'm holding doesn't have a use. There are times when I wish I was holding a different card, but being able to outright choose your card would ruin the AST flavor as well as overpower it.

If I'm not mistaken (and I don't think I am) AST has the widest range of buffs that can be used on others in the game right now.

As far as Celestial Opposition goes, I use it just before using Collective Unconscious to give my tank a regen (or third one, depending) without having to worry too much about dodging an aoe before I even have a chance to cast it. Not likely the best use, but it works for me for now.