the original versus was one game (script was said to be complete one-two years after the reveal), then Nomura probably kept adding stuff (probably making it more complex like KH lol) the World of Versus epic was announced, then it became a single game again.
do you want the Versus XIII from 2009, 2011, 2012, 2013, or 2014? (i know im exaggerating but lawl so many changes).
you can't be so arbitraty with this, you talk about cramming the game and say to throw away all the FNC content except Etro? you're the one cramming now.
ppl don't even know exactly was Versus was supposed to be in the end; everyone was just so so sure cindy never would be a character in Nomura's vision for example (and i personally don't see her matching the early material) and then the designer confirmed it was created for Versus.
everyone just have a vague idea of what that game would be so far, which makes all the ppl crying for it look even more crazy.
It was big enough to be planned for 3 games, if the game would have always simply worked as a one game piece, then FFXV wouldn't be in the state that it is in, it's pretty clear that FFXV couldn't fit all that in one singular title, which is why things are rushed, or not touched upon like Prompto being an MT. Even Tabata admitted that if Kingslaive(which started in 2013 though there is no evidence to suggest Nomura was ok with this, let alone if he had the power to not be, he was on the way out that time), and Brotherhood didn't exist they would have to have made sequels for FFXV, so no it's not that Nomura went off the rails(especially since the FF7 Remake is most likely a 3 part series), he knew that the story he wanted to tell couldn't fit in 1 installment because if they tried things would get summarized or dropped from the story.
The scenario was finalized in 2010, Ferrari got a script in 2011, the changes happened from 2012 and onward.
I say keep Etro because she was the only relevant FNC connection that was in it to begin with there were no mention of Cie'th, fal'Cie, Lindzel, Pulse, so I just though ok Etro, the rest can have similar functions to the FNC stuff but just different terminologies. I personally didn't mind that Cindy was in Versus XIII, I think she would have fit the more lighthearted elements of the game like the roadtrip part, I know it wasn't super serious, probably more serious than FFXV, but not like Daredevil or Batman Returns serious. Also on the changes I wouldn't be suprised if the changes were caused by Square themselves then simply Nomura going off the rails 2014 was the release date of FFXV, the plot leaker said that Nomura's vision would take till 2017-2018 to have been released, therefore changes had to be made.
Also on the topic of the FNC, you could replace all the terminologies with a different name and it would be the same as long as they have the same function. it doesn't really matter.
You could even change the names of Lindzei, Pulse, and Etro and you could get the same effect, the only god in the FNC that has any character is Bhunivelze, so unless Final Fantasy Versus XIII was going to deal heavily with the character which I really doubt it wouldn't have really mattered, if terms got changed it's the function that matters.
Also according to another supposed leaker Cidney was suppose to have character development.