I think the problem for the last twenty years has been that Square still hasn’t found the right formula for the series going forward. Every FF game after FF9 has been radically different from the one before, much more than was the case for FF1-9.
-FF10 ditched the traversable world map for a much more linear experience
-FF12 was less linear and had bigger areas than FF10 but still no world map, and a completely different mmo-
inspired real-time combat system
-FF13 went linear again and even ditched long-standing rpg tropes like towns and optional locations, or the
ability to visit earlier locations and had (once again) a completely different combat system (and no world map
either)
-FF15 was quasi open-world (thus didn’t really need a traversable world map), but ditched the ability to directly
control party members in favor of pure real-time action combat
And now it looks as if FF16 will completely shake up the series yet again, and might not even have a party at all, being instead more like a character action game than a Final Fantasy game. Normally, changing things between installments is a good thing, since it keeps things fresh and interesting, and prevents a franchise from getting stale. But with FF it feels almost as if every entry since FF10 has been a self-contained experiment, and that none of the lessons learned from one game have ever been carried forward to the next one.
Why not stick with a particular combat system and improve it over several games? Why switch between linear and open(ish) world design from game to game instead of sticking with one (preferably the latter)? It worked for the first nine FF games. No one complained that FF9 had a similar gameplay loop to FF8 and 7; the different world, story and aesthetic were enough to set them apart. I doubt anyone would’ve been overly disappointed if FF12 had had a similar combat system to FF10 (as long as random encounters were still gone); who knows, maybe the game would’ve come out sooner.
Every time a new FF game gets announced it looks super cool at first, and everyone thinks that this will be the game that finally returns Final Fantasy to form, but then every time it turns out there’s something from earlier games that people loved that’s either changed or is missing entirely, be it a traversable world map, optional/secret locations, a diverse party, or a strategic combat system. It’s always something. Let’s hope that something won’t be missing from FF16 (like an actual party).