I want them to allow you to have non-inverted camera controls. Inverted only with no option to change is unfair.

I don't like the Zodiac Job system, but I think the License Board could be rearranged a bit better and possibly even augmented, since it's too easy to have characters with most of the top board mastered on a playthrough with moderate sidequests. Restructuring would be nice especially for the tecknicks, where you have to master them essentially one at a time. It would be better for characters to have one or two essential to their archetype, instead of focusing on getting them all.

All gambit commands should be unlocked at the start, having them unlock as the story progresses doesn't make any kind of real sense, especially for tactical players who have really mastered the system.

Other than that, the combat system shouldn't be tweaked at all; it was one of the most important and best-implemented innovations in RPG history. It allows you to have the real-time combat modern WRPG blockbusters are obsessed with, while still having the tactical control of every action that a true RPG demands.