Badass Decay: Leviathan was one of the most powerful summons in early installments (second to Bahamut in III, the King of Eidolons in IV, one of three level 5 summons in V), but became more of a mid-game summon starting with VII, and is now a part of the 6-pronged elemental wheel seen in the latest installments, alongside "basic" summons like Ifrit and Shiva while his old role was effectively given to Alexander. Final Fantasy XV inverts this by making Shiva and Ifrit more badass and elevating them to Leviathan's level.
Contested Sequel: Every Final Fantasy game somehow manages to become more controversial than the last one.
Crack Is Cheaper: The first thirteen games, for Sony consoles, were bundled together as part of the franchise's 25th anniversary. Said bundle's price? $446.
Critical Dissonance: The entire series. Critics almost universally give Final Fantasy games high scores. Fans on the other hand are a heavily fragmented Broken Base. Name any game in the series and, though the proportions will vary, you will find people who hate it, those who love it, and those who don't feel strongly either way.
It is generally agreed that the series has done this, but there is no absolute consensus to when this happened, being the subject of massive Flame Wars. General consensus is it happened somewhere from IV to VII. Each game in that span, in their own ways, radically improved upon the gameplay, plot and/or characters compared to what came before.
It is also generally agreed that the A Realm Reborn relaunch of Final Fantasy XIV signified a second beard-growing in The New '10s. While there have still been debates about some of the games that followed, in general ARR's launch in 2013 marked a general improvement in the quality and effort put into Final Fantasy titles, with XIV itself taking a major lead position with its expansions.
Hilarious in Hindsight: A commonly believed though untrue story behind the series' title; it was called "Final Fantasy" because Squaresoft was going bankrupt and everyone in the company expected this to be their last game, and Hironobu Sakaguchi was considering giving up being a video game designer and decided to let this game decide for him. Instead the game was hugely successful, saved the company and Sakaguchi's career, and is now a pillar of the JRPG genre.
My Real Daddy: Some fans will tell you the series began to lose its way once Hironobu Sakaguchi resigned from Squaresoft, and its subsequent merger with Enix from 2001-2003. Following this came the Compilation, the slew of remakes and ports of earlier titles to handhelds and smartphones, and the troubled development of XII and XIII, all of which lend some grain of truth to the opinion.
People think that the pretty, angsty protagonist only started happening when the games moved onto the Playstation. Either they do not know about Cecil Harvey, or they are actively practicing denial.
Percentage-based damage. The Gravity spell family—which first appeared in Final Fantasy V—is the most famous example of this: Gravity takes 50% of the enemy's HP, no matter how much HP he has. However this first appeared all the way back in Final Fantasy II with the Blood Sword, which always took a certain percentage of the enemy's HP, no matter how large it was.
Popular with Furries: Red XIII from VII, Kimahri from X, the Bangaa race, the various Behemoth breeds, and some of the summon designs ensure that a lot of anthropomorphic fan-art surrounds the franchise.
Tetsuya Nomura became this trope thanks to being the Creative Lead of the Compilation of Final Fantasy VIInote A Slew of Spin-Off titles focusing on expanding Final Fantasy VII. that was a major focus of the company in the early 2000s. When VII became a huge hit, Nomura not only became the go-to artist for many subsequent main series titles, but he became director and producer of several Compilation titles, and fans began to blame anything wrong with the series on him. This is despite the fact that outside the Compilation, he had only ever been an art and character designer; some 2010s-era games begin to credit him as a Creative Producer, but the hatedom for him existed long before then.
After Final Fantasy XIII came out, fan attention for the trope shifted to Motomu Toriyama. Many fans see him as a Trolling Creator and blame him for the poor quality of the XIII trilogy. A bit more justifiable than Nomura, as Toriyama is the director of those games and thus does merit blame for their quality. It remains to be seen how any future projects he's a part of, or just future titles in general, will uphold this status.
When Final Fantasy XIV was first released in 2010, it was panned heavily from critics and players alike for being full of glitches, having illogical gameplay mechanics, and having a lot of Cut-and-Paste Environments. Hiromichi Tanaka was the director at the time and was also the director for Final Fantasy XI. Tanaka got the blame for the failure that Final Fantasy XIV went through, which resulted with him getting laid off by Square-Enix. Although he did make some public gaffes when it came to handling the news media, some fans of the 1.0 game feel Tanaka was made to take the fall.
The Scrappy: There's usually at least one character per game that nobody wants in their party, no matter how good they are.
Sometimes entire games are considered Scrappies in certain parts of the fandom, which is a small part of the reason behind the Broken Base.
Sequelitis: Much like the beard-growing above, a majority of the fanbase is of the opinion that the series is suffering from this (or has been spending The New '10s trying to claw its way out of such), and just like the beard example, nobody can quite agree on or pin down where the rot first set in, or if it's even been a consistent malaise. A lot of oldschool NES/SNES-era fans say VII, a fairly significant number these days say VIII, some point the finger at X, some at X-2, people who dislike the MMO entries pulling resources away accuse XI, and then people were writing off the franchise because of FF XIII... you get the idea.
Silent Majority: These games are best-sellers, but you would not know this by looking around the internet, though. Before examples were removed, the Final Fantasy fandom was listed as an example of the fans who still buy the games and enjoy them, but don't feel the need to scream about it on the internet.
True Art Is Incomprehensible: As the series progressed, plots became increasingly complex and convoluted... and the individual games got more and more critical praise. VII is considered one of the greatest games of all time, nevermind that it's plot is very confusing and was not translated very well to boot. Subverted with some later games; critics and fans have begun to single out poor and confusing plotlines as a weakness of the series.
Visual Effects of Awesome: Alongside Crowning Music of Awesome, this is the other trope that most fans universally agree on, ranging from the elaborate opera scene and destruction of the world in VI, to the warping antics and titanic Astrals in XV. The most common ground for these are a) the ever-present summons, and b) the more recent fight scenes.