Up until XV no FF had done an action type combat system like you'd see in Kingdom Hearts or Devil may cry.
There was this game, that for a Final Fantasy game, was kind of mediocre, but would have been okaysh as its own thing. Came out in 2013. Starred a pink haired girl who was coming back to the forefront after not really being around for a few years. Was action combat. Used a paradigm system to let you change active ability sets on the fly.

Required an absurd amount of precision timing in harder modes.

It felt a LOT like the trailers for ff16. (16 reminding me of that and 15 is why 16 sounds horrific right now)

I know its not a fever dream I had for a week or so.