@Boz: I disagree. I think Survival is entirely the tank's job. That's the only reason the tank is in the group! The rest of us already make the boss pretty mad by ourselves.

I must first admit that my tanking experience is extremely small. Back in BC sometime I did some tanking on my druid (around level 50) in a few dungeons. I've also done a tiny bit of tanking on my warrior (also around level 50) in Cataclysm. My biggest experience with tanking is on my Death Knight in Wrath. Again, just leveling dungeons, but this time between levels 70-78. Clearly I have no raid tanking experience, though I have much raid leading and raid DPS experience. All that out of the way, here are my thoughts:

Tanking was fairly boring. Especially as a Death Knight at that moment in time. I felt like a DPS that was allowed to pull aggro. I didn't feel like I was doing anything to stay alive, which felt like the point of tanking. The reason a Prot Warrior tanks is because he can take it. I don't tank on my hunter (more than 5 seconds, heh) because I turn into a squishy paste. That, to me, is what makes a tank, well, a tank. The ability to SURVIVE. I don't bring the tanks to raid because of their spectacular ability to kill bosses or even really to show me how mad they can make the bosses. I can do that just fine all by myself! I don't do that though because I would die. I'm no tank.

On my DK in those 5-man dungeons, I felt like I didn't have much to do. I'd pull the mobs, then I'd just sit there and go through my DPS rotation, sometimes hitting Icebound Fortitude if the pull was rough enough. I felt exactly like I do as a DPS except that I was allowed to pull aggro and my DPS sucked. I didn't feel like a tank, I didn't feel like I was doing anything to SURVIVE, which is the tank's purpose and reason for being. Oh sure, I could hit a cooldown once a minute, but that wasn't FUN.

I haven't tanked at a high level in Cataclysm, so it may well feel different now. The idea and concept behind these changes has me excited. I don't think a tank's main job should be about threat. It should be about survival, since that is exactly the tank's purpose in the group. Fighting for threat doesn't really make you a tank. It makes you a weak DPS.