These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Bizarro Episode: The transition to the final chapter. With very little foreshadowing or build-up, Finis happens, envoys of the fal'Cie appear to massacre the world's citizens, and Cid departs to a temple that's appeared to usher in the end of the world.
Judging by the comments on the Final Fantasy Answers, the huge amount of characters seen as Expies has only gotten negative reviews. Some say they won't try the game just because of this, others say it's too soon to judge. It's not the first time fans of Final Fantasy choose to hate a game just because of its character design.
The game's announcement sent fissures through the fandom. The official announcement at E3 2014 came mere days after the fanmade English patch was released, and Square Enix sent a C&D to the creators to pull the patch. They did, but this being the internet, it's still out there and fans who want it can still find it. Behind the scenes there was a lot of drama, namely that SE had repeatedly tried telling them to not finish the patch weeks prior to E3. Further, the team felt the patch was not ready for such an early release (the final version that was put out has spelling errors and some parts left untranslated), but the leader of the team did it anyway, because according to rumors he knew or at least strongly suspected the official translation was to be announced at E3 and he wanted to push the patch out before the announcement. Was SE protecting their investment with the C&D or spitting on hardworking fans? Was the patch's early release just the creator wanting to push his team, or was he trying to stick it to the company? Should SE have even gone for an HD release or just translated the game for PSP to save time and money? Suffice to say, this game's release is a touchy subject among those familiar with that fateful week during E3.
Ho Yay: KURASAME X KAZUSA. Also, Ace x Machina, Jack x Eight, and King x Nine.
In the first light novel there's an entire chapter dedicated to Ace and Izana, in which the later describes the former as having a "pretty face that could be mistaken for a girl's".
Les Yay: In-Universe example. In the Alternate Ending, Sice has feelings for Kurasame which she put into a love letter, but she's too nervous to give it to him. However, she accidentally presents it to Seven. It gets even more funny when the latter actually considers the relationship.
LGBT Fanbase: Nine and King, despite being fairly lithe-framed and bishounen, tend to get this treatment.
Cater and Carla get this in small amounts as well.
And when you get a Game Over, your character is surrounded by a blue smoke ...which almost means the enemy is going to do the same thing with you...until NPCs in the game say that only the Magic Bureau, Class 0 cadets and black market traders know how to gather Phantoma, or even know it's existence
The Scrappy: Many hate Machina for his Wangst over his brother's death, being cold and often lashing out at Class Zero except for Rem without listening to them, being The Mole to his classmates for a basically paranoid council, his Face-Heel Turn and his slaughter of his fellow Suzaku (never mind that it's partially because of his memory loss), revived at the end while the rest of the Class Zero students are dead, and effectively becoming the leader of Oriense without being called out for any of his wrongdoings.
Scrappy Mechanic: Throughout the world map save for just around the Academy, you can find Grand Horns wandering around. You're told to avoid them because if they see you they will chase you and you cannot outrun them. When they catch you they're Level 99 and capable of killing your characters in one hit, and are immune to damage unless you nail a kill-sight on them, which still takes a lot of hits to bring them down. They also always attack in pairs so getting an opening to try and hit them isn't easy. This means on your initial playthrough at the least and likely into New Game+, if you wander too close to these guys and they start chasing you, you basically have to let them kill your three lead party members so the battle will end.