It's not like there's much that's dynamic. Most jobs don't have procs and are(or will be in Dawntrail) locked to the 30/60/120 second windows, and most fights don't have much variance, so once you know a job's opener/filler/reopener well enough you can just turn your brain off for that. Things like invulnerability or add phases throw a wrench in that, but they're predictable(and that level of optimization doesn't matter much outside of Savage/Ultimate) and delaying cooldowns to account for them will also become second nature because of how tightly scripted the fights tend to be.