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.
"Funny Aneurysm" Moment: The cover art was designed so that characters from manga that are currently running in some form would appear at the front. This unfortunately includes Beelzebub, which concluded before the game was officially released.
Boa Hancock. Although she does play a big role in the story, her appearance surprised more than one fan as she's not a main character.
Portgas D. Ace. He isn't a recurring character in the series and is only promiment in the arc where he is going to be executed contrasting others characters like Zoro who are far more important to the series.
Some people are also surprised that Jonathan and Joseph Joestar got in before Jotaro Kujo, who's considered the most iconic JoJo protagonist.
Slightly less surprising when you consider that they were the only ones who had yet appeared in the 2012 anime series by the time the game was released.
Luckyman, a man from a rather obscure series based around his superpower of being lucky. He's only appeared in a game once before as an assist in Jump Ultimate Stars.