I think a big part of this isn't so much the mechanics of a given fight more the resources players have that allow them to trivialize so much stuff.
The reason it doesn't really make a difference if a hit knocks 50% of your up off or 75% for example isn't really down to how powerful a healers cures are. It's more down to those healers have near infinite mp.
Same can be said with raising dead players raising a players that's died isn't usually a problem because healers can toss out a half dozen raises and still have infinite mp. There's rarely any consideration for resources. Oh he's dead swiftcast raise straight away. You've nearly always got enough mp. The swiftcast cooldown is probably the only thing that stops you getting raised straight away.
It's the same with dps. A lot of people these days consider invigorate a waste of a role skill because outside of some trash pulls tp is a virtually infinite resource on most jobs these days.. Even if players die 2 or 3 times they still don't really find themselves tp starved.
And in a way it's the same with tanks the difference between tank stance and dos stance is negligible in terms of how hard you get hit and once again because healers have virtually infinite mp it really makes no difference. If being in tank stance meant a cure 1 would heal you but being in dos stance meant you needed a cure 2. Which would actually drain the healers mp that much quicker it might actually make a difference but as is. It just doesn't matter cos you'll never run out of mp anyway.
If a healers had finite mp for example then a dps being hit for 50% hp or 75% hp would likely matter more.
Same kinda thing with to. If being weakened slowed your to regen it might actually matter more that you died. Instead of just being able to get right back into it....
All in all resource management has become largely laughable of late. Which i think is definitely a contributing factor to how easy everything is.