This mod is now included in Postscriptthree's Tweaks, a collection of my mods in one .iro file for convenience. It has a bunch of other stuff too, all configurable, so check it out.

When a character/enemy has a full ATB bar, the battle timer will freeze like it does in wait mode. Characters that are frozen in some way (e.g. sleep, stop) are ignored as to not softlock, and the party is ignored if you are trying to run. If you want a character to wait (e.g. against guard scorpion), you can defend or try to run.

This mod makes things like speed, haste, slow, barrier, and statuses work a lot more intuitively than they do normally. Instead of barrier immediately running out during animations, it lasts a good amount of time without requiring you to slow down the battle timer to a crawl. Haste isn't just a downside of big guard that makes your barrier run out faster, it also lets you take more turns. It's also just more relaxed to play, since your input speed never matters, and you won't get instantly murdered if you do battles with a high speed hack multiplier.

This mod uses an .iro file, which can be directly loaded into 7th Heaven after extracting. There is a setting to make battles start faster by starting the timer immediately rather than waiting for the opening animation. I have not found any conflicts with other mods. I've tested quite a bit with vanilla, hardcore, and new threat with no issues.

I have also added a cheat engine script that can be used instead if you can't use 7th Heaven or don't want to for whatever reason. It should work exactly the same. It's just an injection script, so you can even close cheat engine after activating it and it will stay active.