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: Murfy. Helpful to some, a nuisance to others (and his unconventional gameplay in the Wii U version of Legends only made it worse).
Also Globox in some extent: funny sidekick or annoying Fat Idiot?
Broken Base: Many Wii U owners weren't too happy when Ubisoft announced that Rayman Legends would be delayed for seven months, weeks before the original release date. Their follow up announcement to clarify that the game was already finished and the delay was only to release every version at the same time only made things worse.
Character Rerailment: In Rayman, the title character was much more laid-back and childish than he is in Rayman 2 and onwards, which portrayed him as a more serious character. Rayman Origins, on the other hand, snapped him back to his more childish persona.
Ensemble Darkhorse: Mr. Dark. He's currently only appeared once in the games, and is incredibly enigmatic, fans loved him!
Also Razoff from the third game.
Also Jano the Guardian of the Cave of Bad Dreams from the second game.
Ly could count too, as she's immensely popular with the fanbase, and is often shipped with Rayman, despite only appearing in Rayman 2.
Fanon Discontinuity: It's not uncommon to see fans hating the Rabbids with passion and rejecting their games like they never existed. Most fans of Rayman 3 don't see the game boy advance game Hoodlum's Revenge as a decent sequel neither. Beside this, each games in the main series being quiet differents, there are some who only like the original game, those who only like the 3d games, those who like the first two but not those after, a few who like the series after the second game, and a minority that have enjoyed the entire series.
They Changed It, Now It Sucks: Rayman: Raving Rabbids 2 heralded a period of time where Rayman started playing second fiddle in his own series, until eventually they didn't feature Rayman at all. Fortunately, Rayman Origins came about and put the guy back in front and center, soon to be followed by Rayman Legends.