Technically, FFXII was also functionally an ATB turn-based system - it was just dressed up with a convincingly fluid aesthetic and design that it looked and felt real-time.
Everything you do is based on atbs and charge times, under the hood, and you can see this in the way the fancier spells with longer animations have to queue up and wait their turn - if you input to cast scathe, and the enemy you're fighting also tries to cast scathe, and off to the side Vaan is trying to cast protect on himself, his action bar will be full and flashing, but he won't actually act until the second scathe has actually started - which won't happen until the first ends.
It really was an excellent evolution of what turn-based ATB systems Could be like, and an illustration that they can play in a fluid, active-feeling way while still giving the player full control. You could also set it so that bringing up the command menu to input something paused the game while you made your choices, or didn't pause at all, depending on your preference. It was really very accommodating.
