Buff Jigglypuff highly.
Bring back Mewtwo.
Hopefully I can see Tetra.
Make TL more important in the story mode.
Toon Link/Young Link > Link by a far off margin. Who started the LoZ series again?.. meh.. but Link is a veternan so he should play a major role. Although no getting rid of Toon Link. Best approach for a Link evar made.
Take out Meta Knight and Lucas. DO NOT WANT!
I hate them both, mainly Meta Knight though. I hate Lucas for stealing Ness' thunder. (pun intended)
Hmm, let me see..
A new Pokemon Trainer, I actually already posted this a looong time ago in the Pkm trainer forums... I can't seem to find it. Basically put in another Pokemon Trainer with new generation pokemon. Maybe not all starters this time, but it doesn't matter in the long run. Appeal to the fanboys, Sakurai. Oh, and make it Dawn this time, not that silly Lucas/Brendan/Gold.
Put in Amy Rose. I don't know much about her, but shes in Sonic Advanced and is freakin awesome with that hammer.
Give Ganondorf the power to use his sword.
Ideas for my Main: Toon Link
NEW RECOVERY METHOD, PLEASE. I'm tired of seeing the spin attack:
Deku Leaf, flies up in the air with his Deku Leaf and slowly falls down. Kind of like Peaches umbrella.
Bombs should stay in, although Boomerang should be replaced with his Skull Hammer, Maybe a side swing? It seems fun.
New ideas for Final Smashes (Links/Toon Links):
Toon Link: Plays Ballad of the Gales with his WindWaker - a cyclone comes from Toon Link, getting bigger as it moves whichever way TL is facing, engulfing opponents and doing damage/sending them flying up. See: SSB64; Hyrule Castle.
Link; Also Wolf Link: Midna comes out of Links shadow and puts on the Mask of Twilight (what's its name again, guys? I've only played through it once..) She then grabs an opponent in front of Link, giving Link an opportunity to let Link strike.
Wolf Link: His Triforce glows, and then suddenly WL attacks his opponent just like he does with Triforce slash, doing massive damage to the opponent and having a final blow that knocks them back far.
I can't explain A attacks and B as far as Wolf Link goes, although Midna's hair should play a MAJOR role in his recovery (yes, tether recovery) assuming she rides on his back.
Nothing else I can really think of. Hope this sparks some imagination.