I don't think the movie would be necessary because it's already in game form but...

FF movies are cool (except the "Spirits Within" move, that was kinda corny, lol). I would definately watch a movie about FFX and/or FFX-2.

I think the movie should revolve around Auron, Jecht, and Braska's adventure or something. Maybe Paine's adventure (SPOILER)as a recorder with Gippal, Nooj, and Baralai.
I would watch it Of course, I'm a die-hard FF fan . . .