Oh good I have a few ideas.
First off, if you use Side B and immediately press the dpad up, it goes higher than his actual Up B.
His side b could be a combo of multiple slashes.
I read a thread on how to do that (except they were using it for a final smash) and I'll add a link when I edit this.
The midair Side B would most likely be like Ike's or Zero's except it doesn't freefall, it's a bit shorter, and would do minor damage.
His Down B shouldn't even bring him back from invisibility until he performs an attack. For the fun of it you could add a time slowing effect too.
His Up B is good. I, however, would've most likely made it with more vertical distance.
Oh, and if these attacks were to be created, the freefalls would have to go (aside from Up B).
As for the final smash, you could create a hitbox afterwards that gives everyone on the stage the effect of their shield being broken (the one that makes them look confused) to give him time to recover the final smash.
You'd have to remove the instant kill part of it though.
The regular B is fine. The only thing I can think of is a possibility of a charge feature.
This is just ideas for you. Do what you want with them.
EDIT: Here's the link for the side b idea post:
http://forums.kc-mm.com/index.php?topic=12982.0
