Kid Icarus: Uprising is like the only game Nintendo has produced that does dialogue right, which is probably contributed by the vivid cast of voice actors and the humorous context the Kid Icarus games use. It's also pretty quotable in general, arguably not as much as Star Fox 64 though.
I can pretty much agree with this.
Though after Kid Icarus, I have higher expectations on Fire Emblem: Awakening's voice acting.
But really, Uprising is easily one of my favorite games of all time, not only because of the characters and the humor, but I also like the gameplay (even though the controls were hard to get used to, but it's really a matter of habit).
Palutena is Kid Icarus's likeliest newcomer. I may expect the Eggplant Wizard, Magnus or maybe Viridi as Assist Trophies.
Hades HAS to make an appearence (AT, boss and/or codec easter egg) in the next SSB with the same actor voicing him, or else! He was my favorite character in the whole game BY FAR.
Also, it wouldn't hurt to have a Dark Pit mode for Pit, as in, a set of darker costumes (black wings and red eyes) and voice clips (since they share the same voice actor in both Japanese and English versions, this shouldn't be a problem).
Anyway, obvious borderline fanatic praise of Kid Icarus aside, I still think that Palutena is a very good newcomer for SSB4. She has full potential for a unique moveset. And a new female character is certainly welcome for many people. She could inherit Pit's Final Smash (Palutena's Army), while Pit recieved a new one (the Three Sacred Treasure being the likeliest possibility).