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.
Base Breaker: Pre-release, Labrys was a very controversial character - some like her, others hate that she was put in the game. Mostly because she came out of almostnowhere, and what little information was known about her made her seem like a Mary Sue. It doesn't help that the Robot Girl characters were rather controversial in the fandom. However, once the game was released, people warmed up to her. There are still some people who dislike her due to finding her accent (Kansai for Japanese players, a Brooklyn one for the localized players) ridiculous.
God-Mode Sue: A complaint towards the manga adapation of the game is that Yosuke becomes way too overpowered to the point where he beats Narukami, the main character of the Persona 4 gamesnote (Though he was heavily weakened from his fight with Akihiko), and then proceeds to beat most of the other characters.
Yu's justification for not wanting to get Yosuke a new "nurse magazine" after Yosuke's mom burned the old ones. Yu would feel bad if he was popping into Yosuke's head instead every time Yosuke "uses it."
Adachi has a lot of this with Yu in Ultimax's scenarios.
Teddie's English voice actor changing from Dave Wittenberg to Sam Riegel, due to Wittenberg being a unionized voice actor now. In a subversion, many were extremely pleased Erin Fitzgerald replaced Tracey Rooney as Chie.
Arena being the first region-locked PS3 game ever, to stop Japanese players from reverse-importing the cheaper international version. Quite a few fans were quick to cry foul and boycott the game in fear that other companies would do the same. To be fair, Atlus did make it very clear that both the NA and Japanese versions would be similar in content and released within weeks of one another anyway, so it would give no particular incentive to import the game and there would no problems with DLC support, as that has always been region locked to the same as the disc. However, this didn't help European fans waiting for the game, as the game was delayed from the scheduled release date of August 31st 2012 to May 10th 2013. The EU release being handled by the same publishers as the BlazBlue series, which were notoriously delayed in Europe didn't make the whole backdraft better. Atlus USA is currently trying to do as much as possible to prevent this situation from happening again with Ultimax.
Giving the Protagonist the Canon NameYu Narukami instead of Souji Seta. To be fair, the anime has a North American localization, making the former name more recognizable, plus there is still the sizable fanbase who prefer Yu to Souji.
The decision to include the Persona 4 Arena Arranged Soundtrack on CD & with new artwork as a pre-order bonus with all European pre-orders was well received. The subsequent decision to release it on vinyl & only through the GAME stores in the UK in addition to the CD, with the pre-order bonuses not shipping outside of the UK, just set the angry fanbase off again.
There's even a portion of non-Europeans complaining it's not fair that only Europe gets the soundtrack on vinyl, despite the 8 month delay in the game's release there.
With the reveal of the Limited Edition of the game, the backdraft in Europe got even worse. Now people are either complaining about how everything includednote The pre-order incentive Arranged Soundtrack CD, digital fan pack, Chie's badges, a Teddie keyring, a 300 piece jigsaw, and a tote bag just seems to be whatever they found lying in the warehouse and would otherwise be unable to sell, as opposed to something more substantial such as codes for the DLC, an art book or a figurine. Made even worse when it was first announced to be nearly double the price of the standalone game, though it's claimed it was supposed to be £10 cheaper.
Though it's merely implied, according to Mitsuru following her battle with Naoto in Naoto's Story Mode, her illusion self said "things" about her body. Naoto promptly blushes and wonders just what the hell her illusion self said.
Chie thinks that Labrys is really cute, strongly desires to become her friend and protect her, and is generally really emotional about her and cries when she leaves. Maybe Chie just likes robot girls? Or it could just be that she's The McCoy of the group.
In Aigis' story mode, General Teddie shows interest in Naoto's measurements. Put two and two together and either Shadow Labrys was just being in character, or Labrys is a Covert Pervert.
Speaking of Aigis, Elizabeth seems incredibly interested in her...
One of Shadow Labrys' win quotes is calling her opponent 'cute...and weak'. She can say this to female fighters.
They Just Didn't Care: The opening cinematic uses the Japanese title, Persona 4: The Ultimate in Mayonaka Arena, as opposed to the Western release's Persona 4 Arena in all versions of the game.
Tier-Induced Scrappy: Mitsuru was considered one of the most broken characters in the original Persona 4 Arena thanks to her massive range, extremely useful Furious Action, and the fact that her autocombo does a surprisingly high amount of damage. This garnered her quite a reputation among the competitive community, to the point that one player once decided to participate in a tournament with a special arcade stick that has only two buttons — one for an autocombo and one for a Furious Action — using Mitsuru as a joke. He got into the top 8, only being held from first place because she couldn't burst. It probably stands to reason that Mitsuru was one of the most nerfed characters in Ultimax.
According to people who played P 4 AU, Mitsuru was both nerfed and buffed in some areas, leading to her retaining her spot in S tier.
Yu might have taken Misturu's place in Ultimax, with his ability to deal effciently with just about any situation with his amazing set of specials and supers and his lack of any real weakness.
What an Idiot: Really, you have to wonder how it didn't occur to the researchers on the project involving Labrys that causing a weapon to develop a heart, personality, and ultimately, an ego might result in said weapon taking issue with being forced to kill.
The Kirijo Group trying to create an artificial Dark Hour, possibly right under Mitsuru's nose. Yeah, that's totally not going to go horribly wrong…