Him being a clone isn't entirely impossible, but I don't see how anyone can believe it IS Mwu.

Mwu is dead. His gundam freakin' exploded. Even if he flew out, he wouldn't have air. The fact that the helmet scene was removed doesn't indicate anything, minor details were removed in the movie editions of Gundam 0079 aswell. Yes, he has the same voice actor. So what? Seriously!! Do you think the director's thought "Yeah let's get the old VA back no-one will hear it!". If Neo was Mwu, they WOULD keep that a SECRET. They wouldn't use the same voice actor and everything, because it just creates stupid speculation like this. Besides, his voice actor is exactly everywhere. And I mean, why the hell would Mwu, if he survived, become an evil guy with a mask who steals gundams?!!!!

Again, a clone; maybe. But it's NOT Mwu.