That would be amazing. Yeah, the more I think about it, the more I think that picking Mach Rider over Excitebiker would be a Sakurai thing to do. Not saying it's a downright terrible choice, but doesn't seem like an impossible occurrence. This whole leaks is kind of Sakurai choices: Banjo over Steve, because while Microsoft would've probably wanted the more marketable character Sakurai would choose the fan favorite; Mach Rider over Excitebiker, already discussed that; Chrous Kids coming back as they were previously cut... It's looking more and more real, whether I like it or not
On another note, personally I don't believe the post that guessed these 7 characters, because I honestly doubt Ray was ever even considered for the game, no offense to his fans. His popularity doesn't compare to other abandoned Nintendo series like Golden Sun, Advance Wars, Chibi-Robo (if you consider that abandoned), or even Excitebike. Plus I don't think Sakurai would've had the heart to cut Dixie for a second time. I have a feeling he'd try to throw her in as a last minute echo, unless she's saving him for DLC.