Ah; sorry, I never really addressed your post.
Characters that I think would rock! Magnus, Megaman X, Zero, Issac, Midna, Koopa, (Sakurai's Cat.) Shadow, Tails, Cloud and my favorite gaming character...... Dust! from Dust: An Elysian Tail!
Isaac is already confirmed for the roster. His model is available and his character has a BrawlEX .rel, so he's top priority. There's no way I'd leave him out.
As for Magnus, that's an interesting suggestion; Since I don't own a 3DS, I forgot about him. He could very well make the cut, but it's irrelevant because there's no model for him available yet.
As for the rest of your suggestions...
I'll start with the third party characters. I'm sure you missed it, but a page or two back I mentioned that the project will have very limited support for third party characters, if any. It seems likely, but just keep that in mind. Also, I explained that each third party franchise would be limited to one representative, without exception. That would mean Shadow, Tails and Zero are out of the question. Shadow especially. And, since I'd be choosing the
main character each third party franchise, classic Mega Man would make the cut;
not Mega Man X.
And I hate to disappoint you, but you brought up two "fourth party" characters; Cloud and Dust. I am to understand that both of these characters have never made a canon appearance on a single Nintendo platform. This project is
strictly Nintendo based (which is why even third party characters have limited priority). For that reason, I simply can't add these characters. I mean, I wanna play Goku in Smash as much as the next guy, but it's not a
realistic choice for the game, and I want this project to be believable.
In any case; I've never played Dust. The point of the project is to make as accurate a PSA as possible; I can't do that if I know nothing about the game! Haha, asking me to do it would be a bad choice.
There's no model for Sakurai's Cat, so it's out of my hands.
As for Midna and Koopa... They're just too low key. Koopa especially. He isn't a major villain, or a major character for that matter. He's never playable, never starred in his own game, never was the main antagonist, etc.; those are the main determining factors when it comes to selecting the roster.
Midna's a little more tricky; she's still a major character, but at the end of the day she's just a sidekick. The Zelda Franchise already has a great deal of representatives lined up, so I cant messed around with her. Plus, thinking of a standalone moveset for a flying imp would be strange.
Now, supposing I
did include Midna:
I'd include it as an added feature to Wolf Link.
...So then I'd have to make a Wolf Link, which you'd somehow be able to toggle Link into.
...Which isn't canon for ever Link costume, so I'd have to make it a one slot thing.
Long story short, ideally, I'd love to include it, but unless I get a reliable team established, it's not possible.
But as always, thanks for the suggestions! Anything to get me thinking up new material is welcome, haha.