Even if they attached gameplay to the narrative, fleshed out all the scenes they wanted, and smacked it all onto four discs, it would have been too smurfing long a game. I don't know how they'd split it without feeling like a BS cliffhanger, but it should've been split into at least two games.

Spend a few months polishing the dungeons. Cut down on the fat, add in worthwhile puzzles, and overall give them the right pacing.

Fine tune the combat. Tweak the levels/difficulty of the enemies as the story progresses. Make the dungeon crawling a test of how efficiently you use your resources, MP + items, like Dragon Quest.

Either get rid of the platforming altogether or fine tune it as well so it benefits the pacing and doesn't feel like a pain.

Definitely expand on the other past lives of Fei and apparently the past lives of the supporting characters, or however they tie into Gazel. 60 or so hours and I still don't have the slightest clue who Kim actually was.