Some game ideas (like most of mine) tend to be a little more in the long shot category.
So I didn't want to spam the 'proper' game development thread.


Gambit system for Carbunkles:
A gambit system similar to XII in the actions/traits page for Carbuncles, (and perhaps summons and chocobos too) might be awesome and also useful.


Personalized Bard jingles:
you make a very basic "melody maker" (perhaps available off line, along with character creation);
a choice of a few different tones (harp 1, harp 2 etc), a stave for painting notes, tempo slider, texture background.

Players get 3 or 4 slots to save their 'jingles', (which can't take a lot more space up then a minion or a piece of armor), and select them as the sound that plays when they use Bard skills. (settable in the actions/traits menu).