Maybe Wutai will be hugely expanded upon indeed tho.
Yes, Wutai will surely get more attention this time, especially with President Shinra mentioning it before the Air Buster battle. Wutai will probably get even more stage time in dialog form in part 1 alone. There's so much lore to explore anyway and they'd be stupid not to do that.
Part 3 will then have the rest of Nibehleim/Mt. Nibel, Rocket Town, Wutai, Gold Saucer again (the date), the Temple of the Ancients, Gongaga (again), Bone Village, the Sleeping Forest, the Forgotten Capital, trek to Icicle Inn, Icicle Inn, Snowboarding, the Great Glacier, Gaea's Cliff, Whirlwind Maze and then the ending cinematic.
That's 15 locations, some small, some large. With expansions and the Remake treatment, I'm sure this can fill an entire game.
Same with Kalm to Nibelheim: Kalm, Chocobo Farm, Midgardsormr Swamp, Mythril Mines, Fort Condor, Yuffie Forest (yes, I think she'll join before Junon), Junon (lower and upper), the Cargo Ship, Costa del Sol, trek to North Corel, North Corel, Gold Saucer, Gongaga (still optional?), Cosmo Canyon, Nibelheim.
Also 15 locations, big and small.
Works for me.
I've toyed with the idea of moving the launch of Shinra #26 forward, while Cloud and Tifa are still in Mideel. Cid's journey would book end Part 3, while Part 4 is the return of Cloud and Tifa till the end.
This would be an interesting idea for a Cid-centric game. But I doubt they'll do something like this, as the main story isn't about Cid and neither about the space program and going to space. Also, I think there's too little content for one game from Cloud's subconsciousness to the end.