I think this topic would be even more interesting if it also adds desires from Europeans Fanbase.
From being in the UK I can make a few mentions, but while I've spoken about this in a number of places my sample is far from perfect. Other countries, and simply other parts of the UK may differ durastically
First Parties:
Pokémon: Mewtwo is practically the only requested Pokémon 'newcomer'. Alot of people want Pokémon Trainer to come back, and are worried he'll be cut too.
Mario: Rosalina is less popular, but still big, Bowser Jr is more popular. There was alot of backlash to Rosalina's reveal. The Waluigi meme isn't as strong, but people still do like him. He's less popular than Jr though.
DK: K.Rool is highly requested, but probably less so than the US. Dixie is much less mentioned.
LoZ: Re-worked Ganondorf, though the OoT boss battle is more popular than him sword. Tingle is mentioned about as much as Toon Zelda, but neither are highly requested. It should be noted that we actually quite like Tingle in the UK, but are mostly happy with him as an AT.
Metroid: Rarely comes up. The 'too big' argument barely exists, and as such people rarely consider Ridley. Moreover the Metroid games are generally less liked and a lot of people ask 'who's Ridley?' when I bring it up. Those who do know the series are generally positive about his inclusion once reminded however.
Yoshi: No-ones brought it up to my memory.
Kirby: Oddly not heard Bandanna Dee over here, though the animal buddies are often requested as ATs.
Star Fox: No-one asks for Krystal, and most people want Falco gone.
F-Zero: Black Shadow is more popular than Samurai Goroh, but that's not saying much. The games are unpopular and most people only know Black Shadow as the guy who got Falcon Punched in the youtube video, Samurai Goroh is not well recognised, even after saying he was an AT.
Mother: It's VERY split. jRPGs are more popular in Europe, and those who are fans of jRPGs want both characters to be kept, while those who don't want Lucas gone. No-one calls for newcomers, but we only recently got Earthbound released for the first time on the Wii U, we don't really know who they are.
Fire Emblem: Despite loving jRPGs, FE is the exception. No-one's really requested anyone apart from Roy.
KI: Palutena is fairly popular, but KI:U wasn't that hugely successful here. She's definitely not Elite Four like in America.
Pikmin: Some people bring up Rock and Flying Pikmin for Olimar, but that's about it.
Wario: Warioware is more popular, but this doesn't translate to character requests. People mostly talk about what minigames they want in the stage.
Retro: None are really well requested. The occasional Takamaru happens though.
Other: Isaac is the most requested character Nintendo character to my experience. Shulk gets a high number of requests too. Little Mac is less popular, but still bought up fairly frequently.. though I struggle to tell if this is expectation or want.
Third Parties:
Layton is the number 1 3rd party pick (after Megaman), and probably the most wanted character for smash... Isaac and him battle out for that spot.
Pacman's following is smaller, but still one of the largest.
Square Enix reps are more popular than in America, and there's more interest in DQ, though FF still wins out overall. It should be noted we mostly ask for Moogle (or Mog a lot of the time) rather than Black Mage. Sora and Cloud are practically never mentioned, though this may be my sample. KH is still popular, but not as much... generally we have more nostalgia for Warner Bros (and British kids shows too of course) than Disney, though this is changing for the younger ones.
More Sonic Characters is pretty popular, but mainly because of nostalgia (due to the botched NES release in our country meaning fewer older Mario fans), as such Shadow is practically unmentioned, but Tails and Knuckles are.
Snake is generally less popular, but still has veteran love.
Simon Belmont is about the same as in the west, but Bomberman is practically unmentioned.
Spyro is the next most mentioned (probably beating Belmont, but it's tough to say), with Rayman a little behind, but honestly we're scarping the barrel for requests at this stage.
I also hear a few requests for Arle Nadja, but I'm pretty sure this is my sample; since I play Puyo Puyo competitively I strive to get people into the series, and this has apparently worked to some extent
.