I want to start by saying that when I refer to raid buffs in this post I am refering to buffs which provide the entire party a small window of increased damage. I'm not talking about mitigation or damage buffs which can be maintained to have 100% uptime throughout the fight.
Raid buffs, provided through active abilities like cooldowns or astrologian cards, should be removed in their entirety. while raid buffs exist parties are heavily incentivized to bring jobs whos cooldowns align perfectly with said buffs. This leads to a situation where certain jobs will be excluded from parties when their cooldowns don't align well with the rest of the party. This in turn leads to the situation we have now where all jobs need to be designed around a specific raid cooldown timing hence the two minute meta we have now. The two minute meta forces the developers to design every job to conform to it which heavily limits creativity in job design. Every job must be designed in such a way so as to have a big burst window ready to go every two minutes. This means that every jobs rotation must be constructed such that it generates a specific amount of resource over the course of a specific amount of time. (exactly enough resource to do a big burst every two minutes in our current case)
If Raid buffs were to be removed from the game then the developers would have far more freedom to design the jobs to have a greater range of playstyles. They could have some rotations utilize variable resource generation or even variable cooldown timers. They could have some jobs lean more into proc based gameplay where you get access to using abilities in your rotation that you could previously only normally use under niche circumstances because now your rotation doesn't need to line up perfectly every two mins.
I'll use reaper as an example of a job that would greatly benefit from the removal of raid buffs and a few small tweaks to the job. Reapers would no longer need to hold onto their enshroud uses to get two of them inside of raid buffs, now you can use them at your leisure or when the situation calls for it. They could also speed up the rate at which soulgauge is generated by doing something like making it so harvest moon generates a large amount of gauge and your weaponskills have a chance to change soulsow into harvest moon. This would in turn lead to reapers not only being able to use enshroud whenever they want but they would also gain access to using enshroud and many of the other fun buttons more often.
As a side note the reason I would prefer rotations to use more procs or some form of variance in their rotations is because I am firmly in the camp of static rotations being far less fun and engaging than semi-random rotations. Being able to map out your every gcd on any given boss is just so much less engaging than having to make good rotational decisions in the moment. (post1/2)