What people are saying about Kid Icarus being over-represented reminds me of when people complained about Star Fox's representation back in Brawl. As a Star Fox fan who wanted four characters from the series, I'm glad that people think there's a Kid Icarus bias as it takes the hate off of SF, and people will be more willing to accept Wolf back and Krystal in the next game.
Seriously though, I think that Mario deserves the massive representation due to how huge it is on its own. I would have picked Toad over Rosalina, but I think a lot of people will be pleased with Bowser Jr. due to him being a major villain from the series, he's using the Clown Car (which is iconic to me) and he has the Koopalings as alts (Which is throwing old-school Mario fans a bone in my eyes.) Dr. Mario coming back as his own character is a little odd, but since he was planned for Brawl, and people liked him in Melee I don't see a problem with it.
Donkey Kong I agree feels neglected for how big of a series it is. Although I'd like to point out that we still haven't seen all of the items, assists, or even all of the Wii U stages yet. I don't think it's unreasonable to ask for a third character, especially with the massive success of the Returns games, the fact that Dixie was planned for Brawl, and K. Rool's massive fanbase.
As a huge Zelda fan, I'm honestly fine with how it's being represented. So far, there's five characters, three stages, lots of items, three very popular characters as assists (Ghirahim, Midna, and Skull Kid. Correct me if there's more.) and really, the only other character I can see getting added is Impa, which I do think would be cool.
Metroid is getting some great assists this time around, but I do think there was a missed opportunity for a 3DS stage, and If Ridley turns out to not be playable then that is just a headscratcher to me.
Kirby I think is fine as is. Remember it hasn't had a Wii U stage revealed yet.
I do think it's weird that Wolf was cut, especially with the 64 remake and the new Wii U game on the horizon. The series is gearing up for a comeback so I would think that there would be more Star Fox characters to get people hyped up rather than taking one out.
Pokémon I think deserves a lot of characters as well, what with there being six generations and literally over 700 to choose from.
F-Zero will forever be the most neglected series in Smash, especially since it hasn't even had an official stage revealed.
Mother I think should have Lucas stay, but having just Ness I think is fine since Mother 2 is the most popular and well-known in the series.
Fire Emblem I don't see a problem with there being four characters. The franchise has been around since 1990 and has had 13 games, plus there are a lot of characters to choose from.
Kid Icarus I think it's just a case of a lot of the Uprising assets being easy to port over to Smash when it comes to the items and Smash Run enemies. It does seem odd that Dark Pit would get his own slot, and I can already see some of my friends complaining about it, but in the end it is Sakurai's game and I know if I was in charge of Smash and I had just created a game that had a crap-ton of characters in it, I'd be playing favorites as well.