I like the idea of the unity actions. I really liked the idea of combining moves with other characters from other games like Vivi and Steiner from IX, Palom and Porom from IV, and Chrono Triggers dual/triple tech system. I would like it if a special animation resulted from such moves like the introductory movie.

I don't like it when introductory movies shown cool things that you can't do in game. XI had the same problem with visually teasing a sort of "combo-cast" system in the opening cinematic. I hope XIV introduces a system that reflects what the Lalafell and the Hyur do against the Malboro in the opening sequence.

In my opinion, the concept behind Battle Regimens is fine. Their implementation leaves a bit to be desired. I'd like the ability to set actions without being locked into not being able to do anything. I think your chain system needlessly complicates things but I like your Unity system.