Making Speed useful / adjusting 'Wait' battlespeed

What kind of workload am I looking at if I wanted to say, make it so the moment a character's turn became available, the battle would automatically enter 'Wait' mode rather than requiring a menu to be open in order to pause the battle flow.

I'm hoping to do this for a patch because I'd like to make the Speed stat valuable, since right now, due to how the ATB system works, you can just stack turns by having everyone's bars fill up then wait out the enemy's attack animation, then have all your chars take their turns. I've never liked this version of the ATB.