I have been doing some serious thinking on the matter, and here's where I stand now:
Sakurai can go three different ways with the character roster.
He can give us these new 5, most of the Melee cast, and a few other characters that are incredibly "pop" suggestions who behave as basically clones (Waluigi, Bowser Jr., Oni-Link, Dark Samus, etc.). And those he adds that are not clones are STILL the ridiculously over-requested ideas that aren't that original: King K. Rool, Ridley, Blaziken, etc. The third party characters he chooses go completely against his statements, being the likes of somebody like Leon Kennedy, Cloud, Sora, or Klonoa.
Sakurai will offer a similar ratio of new characters to old, just like he did from 64 to Melee. We will see a few Melee characters missing, but in their place the new 5, as well a secret batch of other goodness. It's a mix: characters that are ridiculously (some would say overly) popular, and a few new ideas that most weren't expecting. The final roster would include the likes of Bowser Jr., Krystal, Diddy, and Ridley, but mixed with more "franchise" obscure characters like Little Mac, Balloon Fighter, Takamaru, and [insert generic FE character here]. The third party selections would be more "Nintendo," but still go a bit against what he originally had said. Likely candidates include Sonic amongst others.
In the final, and my favorite, option, Sakurai will select characters that are unique to finalize his roster. The game will come complete with a reduced roster from Melee, the 5 new fighters, and then some unlockables that capture a more rich history of Nintendo than the other two options. Old-but-goodies like Little Mac and Balloon Fighter appear alongside Japan-only characters like Barbara, Takamaru, and Stafy. Sakurai still includes the more unique popular suggestions, like Krystal, Diddy, and Isaac, but doesn't stray at all into "clone" or "just plain stupid" territory. The third party selections are more close to home, and are strictly characters that were, at one point, "Nintendo": Simon Belmont, Bomberman, Mega Man, Geno, and a few others.
Which option do you wish for Sakurai to choose? And yes, they're written with a bias
If you ask me, the final roster should have "X" amount characters, and I am 90% sure that will include Takamaru, Little Mac, Jill, Krystal, Diddy, Isaac, and King Dedede. But don't quote me on it; worship me
I still brag that I was able to predict Marth, Mewtwo, and Falco's appearances in Melee, up to a year before it was released, and then follow that up with stating Wario, Meta Knight, Pit, and an armorless Samus were in SSB3 (even stating that armorless Samus wasn't a full character, and that Wario and Pit HAD to be starting fighters).