Customizable Victory Pose / Fanfare Selection.
Beginning with Final Fantasy VII & repeating in every franchise title since, unique Victory Dances have become a staple for every party character in FF.
Even in most of the earlier titles, before each character had their own unique version, there were still often variations.
As well, the musical Fanfare "anthem" following battle has been different in most every game. To include the option to select your anthem, along with a customizable Victory Dance would add so much to the experience.
Fanfare could be decided from a track-list while the Victory Dance could be a bit more intricate.
Perhaps devised from a string-of-emotes or selected from a list of new custom animations, maybe even have selections unlocked through various means.
Could also utilize a lot of the really awesome skill animations we already possess, minus the spell-effects.
E.g. let that Warrior whirl his axe up in the air but don't show the crazy red particles, as the idea is to show the entire party cheering more than covering the screen by blaring out mass spells.
Please SE, this' a must for any FF, you know this in your heart(s).