-Finally the Melees. This is the hardest one. Reaper could be a Short Burst job if you slowed down the accumulation of Enshroud meter and made that your burst window. Ninja too could be Short Burst with some retimings and tweaks. Samurai I think should be Sustain DPS, reworking their Kenki bar for like the Focus bar from Vergil in DMC5 (inverse of aforementioned Rage bar, grows overtime and unlocks beeg dmg moves at max but lose most or all of it when hit). Monk can be Sustain too because in my opinion it makes sense, and which leaves Dragoon for Long Burst via some dragon power or whatever. Use a special jump to bounce like a pogo stick for 30 seconds idk. If we're low on Long Burst give Monk a special chant or super saiyan power up every 2 minutes.

Clearly each job would suffer in some way too, but that's kinda the point? Sustain DPS like Bard pull their hair out every time the boss goes invulnerable or some set piece plays out. Short Burst actively dehydrate themselves trying to make sure they have all the resources they need before they realize their burst window came off cooldown 5 seconds ago. Long Burst sit there twiddling their thumbs waiting for their next 30 seconds of happiness to come around. Every job gives and takes something.

Another consequence I foresee is the development of strict "team compositions" which would become stagnant almost immediately. Except, with the current content balance mentality of the devs, this level of optimization would only be necessary for the highest tier of raid team, which are already the group most receptive to "give us one, unchanging way to play and make us master it to a high degree." 90% of content in ff14 can be completed with very imperfect rotations and uncoordinated buff windows as it stands, so an "unoptimized" party comp shouldn't cause problems outside of toxic meta-chasers complaining.

All of this is to create a compromise between the raiders who asked for the homogenization in the first place and more casual gamers who want fun unique jobs.