I've yet to see a problem with it how it is currently. The "penalties" are there for a reason. There's absolutely no reason for you to NEED to camp the button if you're properly timing your rotation on a fight you know you're going to have to stun things on. The only real trade off that you'll be seeing is a slight drop in your total DPS by spacing out your normal rotation to conserve some TP and make sure you can easily react to moves that require Shield Bash. If anything does change on it, I'd like to see it not break the current combo. That can be annoying at times, but hardly anything more than a slight annoyance.

You can successfully solo tank Ifrit(HM), Chimera and keep Amdapor first boss on total lock down all while doing your normal stuff with no issue AND not run out of TP.