Hmm, what I have seen from the other fandoms...
Super Mario Bros: They seem mellow compared to to the others. They don't care that much about how the localization is as log as the game in legally out to their country. They may nip-tic about characters and plot here and there, but all in all, the gameplay matters.
What they want for SSB4: They know Toad and BJ are more relevant, so they expect them. Though some want Geno, Waluigi, & Daisy.
Donkey Kong Country: They really care that much about the series' lore, as well as anything else from Rare(before/during their downfall). Though, they take some things way too serious, as well as other video game series(majority Mario).
What they want for SSB4: They want King K. Rool. Then, Dixie Kong.
The Legend of Zelda: Often debate which 3D title was the best. Some often neglect anything before Ocarina of Time. Fangirlasm abound.
What they want for SSB4: Many want Ghirahim as a new vrep for the series. Some simply want a better Ganondorf.
Metroid: Supports the series in whatever way they can. Major arguments about Other M, though.
What they want for SSB4: Ridley, Ridley, RIDLEY. Nothing else, as far as I know.
Yoshi's Island: Kinda the same as the Mario Fandom(considering this is a sub-series, it makes sense), though, they don't care much for the sequels. In fact, some actually hate the sequels(though, they show mercy to Yoshi's Story).
What they want for SSB4: Many have called for Kamek, since they see him as the only viable rep for this sub-series.
Kirby's Dream Land: Arguably, the most sane, mellowed-out fanbase in all of nintendo. Old Generation? New Generation? Character decay? They don't care as long as the games are enjoyable. Even the spinoffs.
What they want for SSB4: I have heard alot about Bandana Dee.
StarFox: Really broken. To many, there's only ONE good game in the series(SF64). The game after it not only featured perhaps the most controversial characters in the series, but was also the start of Rareware's downfall(according to many). And it gets worse from there, both the series and its fanbase.
What they want for SSB4: Many suggest Krystal, due to the belief that her staff will make her gameplay unique and not a clone. That's still debatable, though.
Pokémon: ALOT to go over. G1 Purists, Tournament Extremists, Shippers, the works. Not to mention fans of the different medias. The Games, the TV Shows & Movies, the Books... dear Lord! Kinda hard to explain.
What they want for SSB4: Mewtwo. They want him back. They also want Zoroark and Genesect. And a new trainer. And those are just the more commant wants.
F-ZERO: I barely hear from them. I guess they don't want to stick our like other fanbases.
What they ant for SSB4: Majority Samurai Goroh and Black Shadow. Really, they'll probably take ANYBODY just so Captain Falcon won't be alone.
EarthBound: From what I have heard, they really want to be heard. And they want the games released outside of Nippon, no matter what.
What they want for Smash: Some want Porky, some want Kumatora. I'm not really sure.