Draco in Leather Pants: Jin gets along well with people, even Noel; he just doesn't say anything about his confusion. His jerkassness/partial insanity is a result of the Ikaruga War combined with him finding out that the brother he killed is still alive and remembering his past. This paid off. He's now one of the genuine good guys.
Foe Yay: Jin towards his Ragna, who also happens to be his brother. Lampshaded in Teach Me Miss Litchi where Jin sprouts hearts everytime his brother says something.
Remember Tao's alternate ending from Calamity Trigger done in a cheesy trailer style for a non-existant "upcoming movie" that portrayed Litchi being an antagonist? Yeah...
Remember when Litchi suddenly sports devil horns when trying to keep both Tao and Carl quiet in her story? Well...
Germans Love David Hasselhoff: Tager is a lot more popular with American players than Japanese players. There are a few major factors for this. First of all, he's a Skill Gate Character who takes very little effort to win with in lower levels of play. Second, his character design is one of the least anime-esque of all the Blazblue characters, as he bears some resemblance to some Marvel Comics characters like The Hulk, Beast, and Hellboy as a non Marvel example. As well as being more focused on what is viewed as awesome in Americans: MANLINESS, being the runner up in that department aside of Bang. Third, the voices. Kenji Nomura is probably just another seiyuu for big guys in Japan. Jamieson Price is something of a fan favoriteMemetic Badass voice actor for big guys. Lastly, the memes associated with him aren't as prevalent in the Japanese version, if they are present at all. The infamous GIGANTIC TAGER!!! meme in Japan just equals of his Japanese voice actor yelling "GAUNTLEEET HAAADDEEESS!"... the joke's still there, but less over the top and recognizable.
Ragna seems to be prone to this, like his younger brother/Rival, Jin. He has also been paired with almost every character from the series. What even adds to this is Rachel's Funny Ending. And just like Jin, this is not limited within the series. There're fanarts and fanfictions of Ragna being paired with Rita Mordio, Kohaku, Heart Aino, Lambdadelta, Souseiseki, Sol Badguy, Flandre Scarlet, Rumia, and more. And then, there's the official April Fool's BlazBlue X Arcana Heart - Crossover Flash Game hosted by the companies of both franchises. Where Ragna is on a date with Heart. Oooooohhh, boy...
Magnificent Bitch: Rachel. Truly proves to be the most powerful of the cast and shows what a piece of cake it is to use the Tsukuyomi unit to defend Kagutsuchi from Take-mikazuchi's threat, all without ever feeling like a Mary Sue or even a Villain Sue. Even in BlazBlue: Continuum Shift she continues to be as magnificent as she is in Calamity Trigger, she just leans a lot further towards being a Guile Heroine.
Memetic Mutation: Carl is known by many people as a pimp, mostly having to do with his almost all-purple wardrobe, complete with a pimp hat.
Narm: Before the start of Carl's fight with Nu-13 he says "I'll do my best, sis. I want to taste your cooking again." in the most dead-serious tone possible.
Porting Disaster: The PC release is apparently a bit buggy, and it uses Games For Windows Live for its online play.
The Steam release doesn't even have online play. And if you have people who can play with you locally? Getting local multiplayer to work requires setting up additional controllers in a separate launcher program, which isn't included with this version. So you have a fighting game with no multiplayer whatsoever.
If anyone hates Jin, it's because he is a "scrub" character. His abrasive and crazed personality is actually rather popular.
Rachel is hated for being god-tier.
Some fans hate Carl because he's very weak. These people tend to not use his drive ability properly, which requires Carl and Ada to attack in tandem. This is very visible with his Astral Finish, as the enemy can easily avoid it unless Carl does some serious work. On the other side of the spectrum, some hate him because of the Clap Loop. Never mind the fact that it's extremely difficult to get the timing and inputs right, or even to set up, since most people with half a brain will want to stay the hell away from Nirvana.
Unpopular Popular Character: Oddly enough, the minor characters from Ronin-Gai who follows Bang would avert this if it weren't, well, for their status as minor characters.