At first I was disheartened by the loss of engage spam for efficiency's sake, but with it gone I'm really able to see how much the insane damage output. I'm not going to say this will be an easy fix, but there should be a ton of easy improvements to make.

I would strongly suggest disabling esuna, positional AI, non-offensive CDs on dps classes.
There's no mechanic in the game that will cause you more trouble than your healer not healing for up to 10 seconds because some mob put a weak poison DoT on your whole party.

ARC is definitely king, but part of that is just because it doesn't waste any time. The squadron AI is basic enough that 99% of the time the CD is both unnecessary and even unused entirely for the duration it's up. PGL is particularly bad as I've seen them cast inner release, and then go through so many other cooldowns that the mob they're currrently focusing dies. Then by the time the PGL reorients itself properly to another mob the buff has already worn off.

Positionals in general just need to go. Keep the requirement or added damage if you want, but the squadron just loses so much damage casting nothing because they're trying to get an additional 40 potency or whatever.

And I dunno, so SOMETHING with ACN. That class has absolutely nothing going for it.