I'd probably change this on a whim every other week, but here's my proposal for right now, presuming rights issues are all solved ahead of time. Also, even though I'm cutting Sheik, I'll still limit myself to the same number of physical slots on the character select screen - 25 - and then presume that the development time that could have gone to another character instead goes to implementing some more stages or something of the like.
Characters in green are included from the original with no changes.
Characters in yellow get significant changes, but remain in the roster.
Characters in red get cut completely, but may appear as Trophies.
Characters in purple are complete newcomers to the roster.
Mario | Luigi | Bowser | Peach | Yoshi | Donkey Kong | Wario | Link | Zelda |
Fox | Wolf | Ness | Sukapon | Kirby | King Dedede | Samus | Captain Falcon | Ganondorf |
| Pikachu | Jigglypuff | Mewtwo | Marill | Olimar | Lip | Marth | |
First up, character changes:
- Mario gets his F.L.U.D.D. down special from future games, and gets a couple of elements from Super Mario Sunshine for flair.
- Luigi likewise gets a tether grab with the Poltergust, and overall gets a couple of additional elements from Luigi's Mansion.
- Zelda has had Sheik removed, and now is intended to stand as her own character, with her magical power being the focus of her kit.
- Fox is now in his Adventures design. Nothing else of note.
- Kirby has a few more classic Copy Abilities across his toolkit for some of his normal attacks.
- Samus has been tweaked to better-represent classic Metroid's gameplay, and her design is from Metroid Prime.
- Ganondorf has been decloned and is now more closely based on his Ocarina of Time appearance. No trident, and no sword. (The sword doesn't make sense anyway, it was only included because the model for it existed after it was made specifically for the Spaceworld 2000 demo.)
Next up, character cuts:
- Sheik has been removed from Zelda's moveset so as to let Zelda's own moveset develop.
- Ice Climbers have been replaced by another "retro rep".
- Dr. Mario has been removed as a somewhat unnecessary clone, functionally replaced with Lip.
- Young Link was deemed unnecessary compared to other inclusions.
- Falco was replaced with Wolf so as to allow for more villainous characters in the roster.
- Pichu was replaced with a more unique Gen II Pokémon.
- Roy was replaced with another particularly recent newcomer.
And lastly, new character inclusions:
- Wario acts as a representative of the Wario Land series, pulling from across that series to have a moveset distinct from Mario's.
- King Dedede is introduced as a Kirby "antagonist", partially due to his unique combination of heavyweight and lightweight characteristics.
- Marill was selected as a Gen II Pokémon due to their prominence in the anime, plus their as-of-yet-unique Water typing.
- Wolf is chosen to better act as a "villainous" pick to counter Fox, and has a more unique moveset that only occasionally calls back to Fox's.
- Sukapon replaces Ice Climbers as a retro rep in recognition of their popularity in the "Smash 2" poll, plus their currently unique fighting game genre.
- Lip replaces Dr. Mario as the de-facto "puzzle game" rep and brings a fresh take on the "mage" archetype in the process.
- Olimar represents the fairly new Pikmin IP - it was either him or someone from Animal Crossing, but Pikmin felt more involved and natural. For both balancing and processing reasons, he only has three Pikmin at a time instead of five - the classic red, blue and yellow trio.
By the way, with this in mind, some of the in-game content would also change. I won't delve into it here, but I'd say that
Fire Emblem would get its own stage as well as
Animal Crossing and
Pikmin, Sprout Tower presumably gets in, and so do stages based around the
Wario,
Joy Mech Fight and
Panel de Pon series.
So, yeah! Hope this is an interesting insight, at least.