I remember seeing 12k hp, 12k armor figures somewhere, but it really depends on group you're going with. After 3.0 I've noticed that there's really no CC used even in pugs, which means you're expected to AoE tanks most trash including Moroes and his adds. That's fine if you're T5+ geared tank but I would expect some trouble with lesser gear.
That being said, I tried to get into Kara on priest alt and +900 spell power wasn't good enough for raid leader. (That's roughly +1600 healing pre-3.0)