The fact that you have to rely on all these bits of hearsay and empty assurances that they had a plan, doesn't help convince me they were actually going anywhere. Really only hammers home the point, and helps me understand why Square Enix felt they had no choice but to hand it to a different lead and team.
If Nomura cared enough and actually had a clue where he was going with the project, he probably could've convinced them otherwise. But someone who bursts into work one morning with an epiphany of turning their JRPG into a musical, probably doesn't lend much hope to investors.

He did. The Invasion of Insomnia, playable parts of Stella/Luna's trip, an entire dungeon within the Dream World Noctis visited, a dungeon in the World of Darkness as well... The sequels were the only thing Nomura envisioned out of the game, and those sequels were undeveloped, especially story-wise. Almost everything he cut was just more content to make the world a little less sparse, and that ran into the good old problem all Nomura games had: running out of time. Iedolas and Verstael's roles were essentially becoming bosses and leading an invasion/military campaign. This was condensed into Kingsglaive and the Ramuh raid... The references to the light alluded to their current role as the ones who would end the Starscourge and tied in to Ardyn's immortality. The summons weren't there. Worse carnage, bloodshed and a more "total war" tone were the main reason for the game having been darker back then, but the central plot had always been the friends going around and trying to get the Crystal back to protect Insomnia from the daemons. 

There was no "vision". That's the problem. People have to accept they would've gotten a more complete product, but our game wouldn't have been different. FF Type-0 for Xbox is still the same Type 0 you got for PSP, but with better graphics and extra stuff. 

But no, this needs to stop. There wasn't "more" to this sort of shite. 

Damn, this is an actual mod that went live...

https://kotaku.com/the-death-of-final-fantasy-xv-dlc-memorialized-in-mod-1830376736?fbclid=IwAR35WLBBDwKEwuBHTPTA0xR-90NoqGirMO_KPU-e2FnELCeilYNXQTkSlAg

Its common knowledge that nomura versus teams were assigned by SE on main line XIII entries during PS3 era. As Versus 13 was not the mainline entry and was too dark and voilent to be a mainline entry hence he was asked to brighten up the game so it could get a wider release, hence it was during this time Nomura floated the idea of making XV a musical as the concept was heavily inspired by Shakespear Romeo and juliet, but the idea was quickly shot down by his team and SE, In process of making it less dark Nomura pitched various stage reboots which would have set them back even further, Hence SE made tabata the incharge.. the only thing Tabata did was cut down the story to make a shorter narrative for a single game, in process ruining the game.

So only if SE didn't force Versus on to main line entry we would have had nomura's game in the same year as tabata and preparing for the sequel.

So as some one who hasn't played FF ever, this seems like a big loss for Square.

Cause from what I've seen and read, here's my understanding of what the situation of FF15 was:
1) Other director had his head up his ass, taking like 10 years to finish the game, resulting in the game going in dev hell (?)
2) Tabata came in and turned things around, actually managing to put out a good final product.

So if that's indeed true, that's a big loss for Square.