By that logic, we already have cooldowns in the game. Every action, spell or thing you do goes on cooldown for 1 turn, then you can do it again. When you are hasted, the cooldown shortens and is skipped every other turn.
The ATB bar is basically your "turn" meter, for when your turn comes up next. Not a cooldown for your skills (the skills that can be compared to attacking, sneak attack, or spells which would require to be restored by resting/mana restoration)
It gets more fun when you consider that Staff of the Magus has a cooldown of 1 turn in Divinity 2. So that you have to spend time to use it again. Anything that requires a time cost is cooldown-gated. Compared to attacks in Divinity 2 that only cost 2 AP. If you have 6 AP you can attack with a bow 3x, as there's no time cost.
For ATB the cooldown is visual and gates your turn, which gates your skills. ATB you're always spending time, so it can be hard to notice. But when compared to true turn-based games it is a noticeable difference.
Asking for cooldowns to be added to a game? You're asking for a time cost.
