Very, very bad news, Mewtwo fans.
A long time ago, someone on GameFaqs posted a heap of supposed insider information. Predictably, no one took him seriously and they all flamed him. One of his claims was that there was a Kirby Air Ride item of which you had to collect some parts, after which, a target would blast your enemy to death. This has been proven true with this update. It's very, very unlikely that it was just a lucky guess.
Where am I going with this? Well he also said his source told him that Lucario replaced Mewtwo. He said his source did not explain what he meant by "replace" however. I'm afraid this does not bode well...
Well, I've searched around at Gamefaqs and I found the post you're referring to. I'll paste it in case the topic gets perched.
Message Begins Here:
Ok, I'm not trying to get attention here or anything, but I've got some insider news.
I can't give proof, and if I could I wouldn't. I thought it was bull until Monday.
I was told there was a stage creator. So far, this news has been correct. So check this out...
He said Wolf was in the game. (I don't even like Wolf, so I don't care.)
Falco is returning.
Ganondorf is returning.
Captain Falcon is returning.
Lucario is taking Mewtwo's Place.
Ness is returning.
Zelda can turn into Sheik.
And there are these items called "Dragoon Parts" I did some research and apparently they're from Kirby's Air Ride. Supposedly, if you collect all three parts you can do some devastating move where you control a crosshair and do a crazy rush or something.
Oh and Final Destination is back.
I wish there was more info squeezed out, but there wasn't. If you don't want to believe, don't. I know there's a lot more to be revealed besides this anyway. Let time prove it, as it has begun to.
Message Ends Here:
The bold in the message is where he, IMO, loses credibility. Then again, now that I think about it, Wolf is
slightly hard to swallow as well, considering Falco's probable return and Krystal practically being a shoe-in.