With the various upscaler efforts, I think the FF7 cinematics are looking about as good as they possibly can without being re-rendered from the actual original sources.
But they're still low framerate, and that sometimes really shows. Right at the very start of the game, the stars look awful as they judder around at 15 fps.
I know Aali's driver uses ffmpeg for playback, there's probably no decoder limitation preventing 30fps (or more?) interpolated cinematics, but there may be other obstacles or even a hard-coded playback framerate within ff7 itself.
Are high-frame-rate cinematics impossible, or just difficult to implement? Some cinematics have field elements layered on top, I could see those being a problem if they're coded per-frame rather than per-timestamp.