Bring back all of the Brawl veterans, as well as Mewtwo and Roy. Then add Ridley, King K. Rool, Palutena, Little Mac, Takamaru, and Shulk. Do that and everyone will love you.
Pretty much. Really unlikely, but everyone generally has this as the basis of their roster, with their own little flairs to it.
I mean, prediction wise, I only have 4 or maybe 5 of those 8, cut a few veterans, and bam. But as long as you have good explanations for your character, and it's actually feasible, you'll be fine.
Which reminds me: I wanted to go on a realistic route and make a cut-45 slot roster. I don't want to go into the Roster Maker right now (pretty lazy), so I cut Lucario, Snake, and Toon Link (which killed me), maybe will cut Wolf/Ike, and added Palutena, Dixie, Little Mac, Takamaru, Mewtwo back, Ashley for my own personal little thing, Chrom, and a slot for some form of a Shocker, retro character (be it Sheriff, Lip, etc.). And of course other veterans and the three newcomers we have.
Cutting those characters was tough, and having only three Zelda slots was absolutely devastating, but I tried to make a unique roster I've never done before.