Astral Fire/Umbral Ice timers are actually bad mechanics at a meta level.

[PyurBlue]

The mechanic is strictly a skill floor mechanic, not a skill ceiling mechanic. Failing the timers mechanic locks you out of your core rotation, and the reward for success is...your core rotation.

That's the intention. It's perfectly fine. Punishment for failed execution is OK.

At its most severe, it turns the class into the only class in the entire game as of Endwalker that is severely punished simply because the devs want to add gaols, stuns, or cinematic cutscenes to boss encounters.

My problem here is with the latter. They're annoying even without resources to disrupt and don't tend to add anything interesting to content. Give us continual control over our characters and everything is fine.