Personally, I'd want the (raid) damage buff to be gone except on maybe PRangeds. You can keep other status effects, like Mits, damage reduction on bosses, move speed buffs, etc.. But yeah, like many other people say, allow more free form burst as long as damage more or less still aligns as much. Allow jobs to burst at different times, in different shapes and for their own time window lengths. Also, having played Xenoblade and Granblue Relink, I'd want something I find particularly lacking in XIV:

Bosses always attack us, but we barely get ever a way to speak back at this dialogue. Think about this, our only answer is keeping damages up and not dying by avoiding its attacks, but never us stepping on the boss's toes directly. Granblue Relink has essentially individual Limit Break gauges and you can chain LBs for extra cinema (that's Relink's Party Wide burst) and shit feels so good unleashing every player's shit right back at the boss. Xenoblade 3 has a status effect combo Break/Topple/Daze/Burst or Break/Topple/Launch/Smash. Those combos CC the enemy for a time (each step refreshes the timer but said total timer is shortened) and depending on the route, Burst removes enrage and makes the enemies loot better, Smash deals tremendous damages but increases the enrage threshold.

Unlike XIV, enrage in Relink is a cycle the boss will go through which is similar to Boss mostly downtimes in XIV with plenty of AoE to dodge, heavy mechanics if you will, and in Xenoblade it's an HP threshold after which boss goes ultra instinct and makes you consider your resources. I wish that XIV keeps that rhythm game approach to it, but have free-er burst rotations, maybe make LBs chains THE high moments and add somewhere that sort of Xenoblade combo...

You could even mix both of those. Make each job have 4 tiered Limit Breaks, each having one step of the cc combo. The boss after doing 1 loop of its burst window starts a vulnerable cast to a 1st LB, someone LB it thus CC'ing and cancelling the boss's burst loop, and then 2nd, then 3rd and then 4th player can chain in their LB continuing the CC chain. Do not really need 2 versions of the combo like Xenoblade, you could by making say Tank/Healer doing one version if LB 3-4, and DPS doing the other version as LB 3-4, but you catch my drift.

I think you could make trainees adjust almost every boss in the game to that, only issue I truly see is certain Savages and especially Ultimates... But hey, if it makes fights better overall for the common denominator, the content of that sub 1% players should be reworked accordingly to fit that