Oh boi...
Kirby. While I appreciate the themes we have already, it really lacks a lot from recent games, amazing themes like CROWNED, Moonstruck Blossom, Royal Road, Another Dimension were nowhere to be seen in Smash 4. So just some from each recent game. Doesn't really have to be remixes, the original tracks are good enough.
Metroid. More variety. Diggernaut would be great. My big request of course is:
Star Fox. Like, can we stop with the SNES Corneria, Area 6 and Star Wolf remixes? quite tired of them at this point, hopefully some Star Fox 2 themes since they have pretty distinct music styles from the rest.
Xenoblade Chronicles X. Fear they are going to skip over this game in favour of 2 music and they are probably going to pick the songs that are too similar to 1's to make it more redundant, if not, hopefully they add a few from X.
Style Savvy. Since we got a Trendsetter remix in 4, would like to see a couple of more from the most recent game, Styling Star, I feel a battle remix for Girls be Ambitious and Maria could work well.
ARMS. If we don't get a rep or a stage, at least use music in the boxing ring from Punch-Out!
And some more indiviual tracks I would like to see.
And some dream stuff, like Tales of tracks.
And I could go on and on.
