Here is a list of Characters I have been thinking of over the years for a SSB4:

1. Noobs- Dialga/Palkia (Wii U/ 3DS), Louie, Prince Fluff, Vatti (3DS), Ghirahim (Wii U), King K. Rool and Dark Kongs (Wii U), Shadow and Team Chaotix (3DS), Waluigi, and Layton, Luke, and Don Paolo.

2. New Items- All other items from Pokemon (and make Pokeball variations), Wooden Shield (TLoZ), Rainbow Star (SMG1+2), and Parasol (Kirby)

3. Returns- Roy, Mewtwo, and Pichu (but put him with Pikachu like Zelda/Shiek)

4. Veterans- All but Pikachu (solo, as explained above), Jigglypuff(replace with Wigglytuff), and Toon Link (Replaced by Vatti/Ghirahim)

5. Final Smash Form- Create a certain pattern on the touch pad to preform a Final Smash, no patterns are alike and cannot be shared (that means only one pattern creates that characters Final Smash)

6. New Assists- Gen 5 Pkmn, Tetris blocks (which flatten your opponent but can be avoided more easily than Snorlaxes), Otacon (Much like Resetti but is only activated by Snake), Lumas (eat items that appear and work as bumper items that can move freely), Count Bleck (replaces clock but also causes continous damadge like the flower stick), and Petey (makes all surfaces slippery so that no one can aim a good ground attack; head can be used as platform by only playing as Bowser, Peach, Mario, Luigi, Yoshi, Wario, or Waluigi)

I always thought that someone captured Olimar, Louie was still stuck in the cargo hold, eating what is left of the organic materials because no one remembered to open the rocket cargo bay, and The President got filthy rich and bought a mansion after he retired. I also always thought that those guys are just the kids and relatives of all three of the Hocatain Heroes.

P.S. Olimar cannot get kicked from SSB, because he is the only one in his franchise that is easily recognized and has a good relation with Pikmin. Not like where Louie tries to hold himself back from a Pikmin eating frenzy and where The President cracks a whip over the Pikmin's backs to keep them working.

When I remember playing SMS when I was younger, there was more areas on the map than available to you when the judge tells Mario of his crime. We could see a hypothetical add on to the game, like the new Elder Scrolls expansion. More levels would be good, along with a two player mode (and maybe a four player once you beat the game), waterproof Yoshis, more F.L.U.D.D. nozzles (make E. Gadd upgrade him along Mario's adventure with coins obtained from stages and/or episodes(like a Swiss Army Knife), and indefinetely use some of the SMG2 ideas, like having your own place to crash (without rent) with new people coming every episode/stage you complete.

P.S. Petey was one of the best bosses I ever faced, along with King Blooper. So make them appear in variations according to the geography of the stage/area.