to me the reason most people have a problem with a battle regimen concern the locking you out of action and the boring animations of the skills. i personally like the coordination that it takes to do a br successfully, but i do have some things i do not like in it and the magics in general honestly.

1. it locks you out of actions while stuck in br mode. this would be an easy fix if say you use a tp move it removes that tp from your bar until the br begins. this would stop the lock out issue and allow you to heal/attack while waiting on others. if you use a magic skill the mp would do the same.
if the regimen was canceled for any reason the tp/mp would be restored since it was called for but never used.

2. the animations are horrible. the same it true with all magic throughout the game and weapon skills also. this game has too great of graphics to have such horrid animations. the same it true for battle in general not just the battle regimen though.

3. people want skill chains involved. i would love to see a combination of skills used in a battle regimen to cause a huge attack during it with a different animation than the individual attacks. they could even give an animation showing the skills combined would be fine with me.

i think just implementing these 3 things would solve most if not all of the issues people have with battle regimens and would make using them alot more fun. that being said i think we just need fixes like these instead of removing the whole system.