I'd rather we get a quality FFXVI then something that's just there to be new and "exciting", I'm fine with new, I'm fine with it really, but i'd rather a FFXVI turn out to be the next FFVIII or IX in terms of quality than to be a XV or worse XIII level of disappointment. This isn't the PS1 era anymore, they want to make big games, incredibly ambitious titles, so I want them to deliver on that, so if it means we have to wait till the PS5 for FFXVI fine, just don't make it terrible, don't make it feel like a waste of time. I care about quality, I'm not going to be excited just by seeing a trailer of FFXVI for the PS4 and the game comes out, and it's the same quality as FFXIII, with the storytelling of FFXV. If Square can do everything on this list, and have them be quality titles, then you know what I wouldn't really care if they are off the same worlds, because hey I'm getting quality games, and FFXVI can come out at any time no need to rush it. Hell I doubt the Squaresoft days can really be compared today, games are just harder to develop now than ever before due to the changes in hardware people expect more.
The problem is that, if they tackle on all those titles that you mentioned, XVI wouldn't be receiving all the care that such a title could be receiving, and its priority would be pretty low, like what happened with Versus all those years. I know about the different internal divisions, but it's still something that would affect that particular game's development in a way or another, and those people would be better off working at new IPs or helping with what are supposed to be the next big titles (VII-R, KH3 and XVI), rather than retreating and doing the same thing all over again.
It's also about brand fatigue (both ours and the developers') and awareness. What need did they have to revisit FF X? Yes, X-2's battle system was great, probably the best in the series, but beyond that, X didn't warrant a sequel, and much less one done like that. Those gameplay elements could have been used for a different project, be it a FF or not. It's why I'm happy about the seemingly new approach with DLCs and expansions, even though I'm not a big fan of how they're usually dealt with by companies.
I really don't understand wanting S-E to spend 3 or more years on something that we've been fucking seen for 10 years and that wouldn't be that different compared to what we actually ended up getting, as flawed as XV is. Clinging to the same thing and not moving on seems exhausting to me (as well as a time waste, as I strongly believe that they're not doing XV sequels or a reboot with Nomura's take on the game).
Basically, I don't want to be over 30 and still be waiting for XVI to release, having only a FF backlog that is all reboots, remakes and spin-offs. The fact that they would still working on XV in some way or form at that age would be depressing, considering that the first trailer was released when I was 13.