It’s kind of funny that even leaks contain Photoshop crap. Yeah, I don’t believe that “Star Wolf” thing either, and the caption under it says something along the lines of “Urufu” (straight up Japanese 102 there for ya). That was Fox’s group, I believe…. errrm yeah. What really interests me is the whole Taboo thing. I have no clue what that is.
Arguably most of the characters that were left out were either too much of a clone, have a similar replacement (i.e., I’d like to think Lucario plays just like Mewtwo… he’s just an updated ver.), or were not popular enough because, yes, tournament popularity can do wonders for a character.
I don’t know how many people actually do care, but Ephriam dear I am willing to debate the game with you. 
Ice Climbers are fantastic, unique, and have a cult following. Jigglypuff simply stays because she’s an original. It’s been said that Lucas plays differently from Ness. Marth is back because he’s awesome (Roy was just so low tier that it wasn’t even funny… same as Mewtwo. Luigi isn’t a clone at all and has different move sets, just like Windwaker Link.
Falco, however… ugh. I just hope they make him not so cheap.
AND YAY FOR POKEY. It’s also bad that I own a R.O.B. It never worked. Just like my Power Glove.