Tanks have a lot more cooldowns to use than they used to. Fundamentally though, our difficulty model is dependent on requiring a stable of healers to keep the tank up. If the tank has too much control over whether he or she lives or dies, then your success or failure has a lot more to do with the skill of that one player rather than the coordination of the raid as a whole (which is where we want it).Right now, it feels exactly like GC is describing, tanks live or die depending on the skill of the healers and the tank does not have enough control over our own lives. Sure, the days of 30 minute shield walls are gone, but only because encounter designs require it. To many bosses in cata have followed the "I have a hard hitting ability that I use exactly once a minute and if you do not CD it you die". Fusion punch, Sarth's breaths, Vezax "kite" phase, Soul Repear, Mimiron's plasma blast, Festurgut's 3 stack. I hate being forced to used a cooldown on a script, and not as an O SHIT SOMETHING BAD HAPPENED.
I guess this is more of a rant about encounter design as opposed to lack of cooldowns or tanks controling their own life, but there is no such thing as a "CLUCH COOLDOWN" that saved the tanks life anymore like there used to be.
The last part: "coordination of the raid as a whole," this can easily be solved by balancing the external cooldowns, in which paladins are still way to strong in that category and new tree form notwithstanding for a tank cooldown, have none. Working with healers so the raid does not use 5 cooldowns at once and as a result have none for the next ability falls into what GC is talking about but again feels to scripted because of the way big boss abilities have worked in LK.