I find playing an aggressive tank rewarding like trying to maximize dps while healing. Also when I tank I try to maximize the dps output of my healers too but that's through proper cool down use, not vitality accessories:-p

If you can survive your big hits then extra HP isn't really helping too much on the healing side. Damage intake rate is predictable after a few pulls and that's what is important not how much extra hp bloat a tank has. Now tanking progression content? I haven't done that in 3.0 so I wont comment but like all things it is probably do what is needed to stay alive and put the rest in str.