Young Link's appearence in OoT 3D is a boost in itself, but can also be flattened by it's release date... But Toon Link isn't looking good either, which is why both should get in. The release of Skyward Sword, however, could mean something...
I understand someone here was also speaking of Event Mode ideas? Because I have some, here they are:
1: Master of Illusion
Character: Zoroark
Enemies: Red Zoroark, Blue Zoroark
Goal: Take out the others in 2 minutes. No items, Stage: Lostlorn Forest
2: Boat Damage
Character: Young Link
Enemy: Toon Link
Goal: Survive until the boat crashes. Items on, Stage: Pirate Ship
3: Aura and Shadow
Character: Lucario
Enemies: Shadow Mewtwo, 25 of them, weak as multiman
Goal: Beat all the fakers. Items on, Stage: Battlefield Melee.