Honestly, I agree with this, at least to the degree that I think either invulns need to be removed or fight design need to be rethought, because right now I think it's making tanking even less interesting on top of all the other issues. The vast majority of fights right now have at least one or two moments where you essentially ignore a mechanic, tank specific or otherwise, and resolve it by hitting a single button. It's partially on the designers for letting the tanks do that, but it does feel like a fundamental issue plaguing tank design at the moment - particularly because there's such a gulf between the strength of them in high end content (it's no secret that Living Dead is a far cry from Hallowed Ground in basically every part of the game). One other solution I've vaguely considered is just changing them from pure invulnerability to either extremely heavy mitigation (think 75-90%) or something more interesting like massive self-healing for a bit; keep the "panic button" feeling while leaving room for the designers to stop the tanks from outright ignoring certain mechanics.