As a massive fan of the middle era of Final Fantasy games: Final Fantasy 9
Hear me out.
The combat was really slow and clunky, even for a turn-based RPG (yikes!) and the sheer amount of time you spent waiting for the black swirl to finally disappear and for the camera to pan into the battle got so damn tedious. It was like a full 30s of punishment just to get into making your first action in a fight, I swear, and those fight encounters came thick and fast on the world map.
The soundtrack was thematic but really uninspired and unadventurous for an FF game
The skill development was closed in and didn't really allow for much choice in what skills you could learn and half of the skills you did learn were mostly useless unless you looked ahead in a game guide or you reloaded a save to deploy the relevant skills for the upcoming boss battle.
Plus you basically needed foreknowledge of the game or a game guide to know how many items you'd need for the synthesis mechanics, or otherwise you'd be learning one skill on one character for ages before you could use that single item to teach the next character their skills, often the same ones.
The playable characters were all one note and they felt like they were written as placeholders with the intent that somebody else would develop them from caricatures and cardboard cutouts into something with motivations and character arcs later in the development. Mild spoilers ahead but it's an ancient game by now so deal with it.... Vivi, the soulless facsimile, was ironically one of the only characters who had narrative development but that was mostly plot-driven and he didn't really change from being a naive child who asks babby's first existential questions, and the story just kinda developed around him.
Zidane just wanted to chase girls and... that was about it.
Steiner was just a mild antagonist towards Zidane and whenever he had a place in the story it was "I'll protect you, princess!" or "I am sworn to the Queen, the realm, and to the princess. But how can I uphold these vows when they conflict... yet again? Oh well, never mind."
Garnet/Dagger was just another typical FF love interest trope and for a quarter of the game they just decided that she'd be mute because they were too damn lazy to bother writing any dialogue for her so she was effectively sidelined.
Eiko is an exception to this - she was a developed character with an arc but she came into the game so late that she barely had any time in the spotlight.
Freya was just "I am longing for my long-lost love, Sir Fratley" and then, when Fratley turns up in the first 1/3rd of the game he's just like "Oh, um, I have amnesia. Who are you again? Anyway, I guess I'll be going now. And I'm taking your relevance to the storyline and any opportunity for character development with me. Goodbye!"
Amarant was an antagonist who just swapped sides out of the blue and just shook his head at decisions, and he came into the game way too late to feel involved in the story in any way.
Quina was the typical gag character which is fine but when the rest of the party has less of a story arc than your gag character, you're doing something seriously wrong.
The setting was fine, although not to my tastes, and the world map felt constricted and very railroad-y: you could only visit a couple of places most of the game and often you'd leave a location only for it to become permanently inaccessible which ruined a whole lot of opportunities for development of the setting. A lot of the places you'd get to visit would be closed off/sidelined from the game after the first visit, if not blown up, and this made any investment in the locations feel useless; why would you bother to explore characters in a city when the last few got destroyed and this one is probably 5 minutes away from being blown up next? Even if it survives, you're probably not coming back here anyway so the characters here are probably going to be inconsequential. And by making most locations inaccessible for large parts of the game/the rest of the games, this often creates a lot of missable items (or events).
So much of the setting was one-note, filled with bland architecture and bland characters that were barely indistinguishable from each other.
FF7, by comparison, had the sprawling undercity slums, the furturistic overworld, the hippie canyon that was an uncomfortable pastiche of vaguely Native American-esque tropes, the mysterious village of the main character with the ominous mansion and an even gloomier mountain range that you get to explore, the adventure casino and the downtrodden slum miners' village beneath it, the military installation/city thing, the beach resort, the reactor town with the eco-resistance fighters set up in it, the post-WWII largely-Japanese (but also kinda Chinese) village which was trapped between two worlds...
More than this comparative lack, a lot of the FF9 locations felt really underdeveloped and like one-note variations on vaguely mediaeval themes. Burmecia is the perfect example of this chronic underdevelopment - it was supposed to be an entire city and when you get there it's a couple of streets and a few unoccupied houses that somehow, inexplicably, lead to the courtyard of the throne room/castle. And that's it. An entire setting which is supposed to be one of the biggest cities in the Mist Continent (according to the story) is just... a few empty streets and not even an actual castle or royal residence to explore. Instead of being an opportunity for Freya's character development a couple of the residents who were actually still there just say "Freya, you're back! Protect the king!!" or "Freya, you rescued me. Thank you for returning to Burmecia in its time of need!"
I guess the mini-games were pretty fun though?
All in all idk why FF9 gets the accolades that it does. To this day you'll regularly hear people raving about FF9 as their absolute favourite from the series and they'll wax lyrical about the character development and the setting.
Ask them how a character developed from their introduction to the end of the game, though, and they'll fall silent. Or ask them which locations of the setting were the most compelling and they'll just explain why they loved one of about three locations that were actually more developed than the rest of the mostly-forgettable locations that you're forced to trudge through.
I suspect that it's just a nostalgia kick for people who were in that sweet spot of forming core memories and when they first played FF9 or something.