To preface, if you're going to quote, please consider actually including text other than "Snip" so I know what you're referring to.

Quote Originally Posted by Lyrica_Ashtine View Post
[...][1] [Healers dying, tanks failing to be the main target, dps losing dps]
[...][2] tanks performing enmity actions on the boss would be normal too. But they are unable to do so as the boss cannot be targeted or is invulnerable.
[...][3] [Healers dealing damage, Thordan EX anecdote]
[...][4] Paladins pretty much have to repeat their Rage of Halone combo to build up enough enmity to last through the Ultimate End phase.
[...][5] [T13 video] While there was time to Provoke, any form of action being taken before the next tank action has effect will outhate the effect of Provoke.
[...][6] I'll just repeat it once more, as you seem to keep ignoring this:
[...][7] [Adds, bosses with pre-set enmity on spawn]
(1) Excuse my paraphrasing, but the described scenario appears to be easily solved by not panicking. The healers aren't killed outright and should move to the tank position. The tank is performing their role as usual and the DPS roles are losing a most likely trivial amount of damage.

(2) When the boss is displaced, the tank's role against the boss is effectively suspended. They cannot manipulate values against the boss in a meaningful way. Thus tanks should have ensured that enmity is sufficiently buffered, whilst considering their DPS and mitigation responsibilities. Healers on the other hand continue to function normally, their responsibilities and the costs for their actions should remain as normal.

(3) I will never argue against healers dealing damage. What is important to highlight is that in the anecdote the healer became the main target but wasn't killed outright after the phase change despite several strikes from the boss. This is in no way a healer being "punished for pushing their limits" as the tank got the boss back without deaths. If this happened every time and each time the healer died without neither the healing nor tank being able to do anything about it, then yes, it would be "punishing". Instead it shows that a tank can solve the enmity problem with their available tools and reacting on the spot.

(4) Paladins having trash enmity generation is a job-specific problem. I do not think that a wide-spread encounter design change is an appropriate response to it. With or without boss displacement phases a paladin will suffer in this regard.

(5) The DPS is clearly at fault. A tank cannot prepare the end of the enmity combo for that transition and enmity is visible to all combatants even when the boss is displaced. This is not hidden information and the DPS could have waited accordingly. A dead DPS deals no damage.

(6) Ignoring what? I've been replying to all points you've presented more than once with the argument that future encounters are still only conjecture on our part and arguing change on content that does not yet exist is something I don't support. If Squeenix does end up making encounters that are tailored to fuck with healers, then sure, that's terrible. But there's no evidence supporting that future any more than there is evidence against it. Adding to that, current content does not have encounters that in my opinion warrant such a change.

(7) I'm afraid I don't understand what you're getting at with the examples given, or what you mean by "If 'management' and 'ability' was really a thing". The adds (assuming Goblin Snipers) are a piece of the encounter puzzle and easily defused threats. Bosses with pre-set enmity appear with no displacement phase in-between. They could just as well appear with zero enmity and quickly end up in the same place with a Provoke and enmity combo. Even if a healer or DPS generated initial snap enmity, a small change to Provoke timing would probably fix that problem.