How important is "proper" DPS rotations for PUG groups?

[Ryel]

Short answer: Depends on the content, but it's always in your (and the group's) best interest to know / be able to perform your rotation.

Long answer: Generally speaking any content with an enrage or a DPS check will require the group to be performing at a certain level DPS wise. If you are the one DPS that is under performing by a large margin then you are certainly holding the group back often leading to wipes, frustration, kicks, etc.

This really only applies to primals / coil / Alexander for the most part though, dungeons / tower climb / extra content are usually seen as more casual avenues and aren't tuned in a way that requires the entire party to be playing optimally at all times so you can usually relax a bit more when doing that sort of content (relax but not completely slack off that is).

But yeah if you can take the time to learn / perform your rotation to the point its mostly muscle memory you'll only see benefits in the long run.