Midna --mild spoilers for those who haven't played the game yet--
I just finished beating TwP last night, awesome game by the way. Anyways, I think Midn could be a pretty cool addition to SSBB, even if a move or two would have to be improvised a little. Heres a couple that I thought of.
***********************--SPOILERS--***************
up+b- Midna does the turns-into-a-billion-particles thing, and flies into the air a bit, knocking aside anybody in her path. Or she could do the whole teleport move that she does with Wolf Link later on in the game.
down+b- Midna turns into a shadow for a couple of moments, allowing her to dodge most enemy attacks. Her movement speed is considereably slower, however, and the effect only lasts for a couple seconds.
side+b- Midna does a dark anergy attack, making her arm-thing shoot out a bolt of electricity. Does some mild stunning to anybody who comes close.
b- Midna does the thing she does when teleporting others, making the target fly into the air in a cloud of particles before rematerialising a moment later. While doing this, Midna can change the direction of the teleport very slightly. This does a fair bit of damage, but is slow to execute and leaves Midna open afterwords. If the target's damage is high, they will most likely teleport right out of the arena.
The Smash Brawl Super attack- *****A VERY LARGE SPOILER NOW!!!******
Midna uses her dark matter-particle pieces, and transforms into the nine-legged huge beast thing, and channels the energy into the target. Basically an instant KO. To be reading this, you must have beaten the game already, so you know what I'm talking about.