Kirby has always had a fair ammount of representation, two original levels and the N64 one and numorous items. Not to mention himself; with his copy ability, he had a whole lot going for him, and was one of the most unique fighters. Hints of other enemies he's copied are the basis of his moveset.
The other franchises need love too though, including Metroid, Donkey Kong, Sonic, Metal Gear Solid, Earthbound, and Fire Emblem. I'm not a big fan of every single one of these of course, but I'm pretty sure fans of these series' would appreciate them getting equal attention to them, afterall, they have enough content within them to warrant more. Oh, and I am aware of the relation between characters like Donkey Kong, Mario, Wario and Yoshi, but since they have been appearing in they're own games (Like Donkey Kong Country, Yoshi's Story, Wario Land and WarioWare), they've really established themselves as seperate characters, and seeing them get more attention isn't at all a bad thing. If a Kirby spin-off series went through and Dedede was in some penguin kingdom, mingling with his penguin friends, trying to save Northern Pop Star from greenhouse gasses destroying their icy kingdom, then maybe King Dedede would deserve more attention, and characters from his own respective series. (Obviously the reason why he overtook Dreamland, I'd be pretty mad at those ****ed carbon-dioxide emitting denizens too.) I wouldn't rag on Kirby having too many characters if that were the case.
I don't care who's making the game though, this is a tribute to all of Nintendo's historical veterans. I'd like to see more too; Pit was a welcome suprise. I knew nothing of him, just as I knew nothing of Ice Climbers, but it's cool seeing them nonetheless, and researching their origins was a fun way to pass the time.
Speaking of which, notice how I didn't include Ice Climbers or Kid Icarus. Thing is, they really don't have a whole lot of games and it's kinda hard for me to say that there is a lot more needed to show them off. However, digging up characters like that and putting them in the game is still exciting to me, and I'm fascanated.
So in conclusion, not EVERYONE needs more characters; if Samus was the only playable Metroid character, then that's not a huge deal, the other Hunters didn't get much air time, and who would they choose? Ridley's pure boss material, unless I'm proven otherwise. But there needs to be more Metroid stuff nonetheless.
'Dat true!