They can reduce the mobs HP to 1 and the tank and healer wouldn't be able to win because "hur dur I only hold aggro and mitigate or I only heal cuz im a HEALer"

What you've suggested where it's only tank stance or go home is exactly that. Only one singular possible playstyle. What we have now is two that can clear. Sure one is more objectively better than the other but at the very least they can both be played with and cleared with. Tank stance or get critted to death? Yeah, fantastic. /s

Yeah the RDM's will probably be able to do it considering their goddamn ability to both raise AND heal. Tank busters? Sack and raise. Oh look, they did it, and considerable faster than the "fantastic 8 tank comp". This is a pointless argument.

It's also well fricken known that no one wants to play tanks or healers. It's also well firetrucken known that everyone wants to play DPS. Why aren't we changing this? Why are we happy to stay in the archaic idea of pure trinity or go home? It's not perfect and we all know it. What SE have down so far is a step in the right direction. DPS queues weren't hour long in HW because would you believe it? People WANTED to play tanks and healers. Why? Because they were able to contribute and feel strong. This ofcourse isn't the only factor as there are many others such as two frocken DPS roles and no tanks in the new expansion or the failure to deliver on tank balance when it was promised instead of a new tank. But I believe it is nonetheless a big contributing factor alongside those and the responsibilities thing. Being a protector is not popular and if you base your tank role around that and only around that then that small pool of people is all you're gonna get.