I think the tanking meta basically killed itself when people got it into their heads that actual mitigation doesn't matter and the only thing they became concerned about was pressing all the buttons to push numbers harder to get faster clears under the notion that you mitigate all damage if the boss is dead.

I'd much rather Tanks be rewarded by being that impenetrable wall of defense instead of having a healer hold their hand. You see stats focusing solely on attack power but we get nothing to increase defenses.