Honestly, Snake has bigger problems than brighter colors to deal with in regards to his inclusion.
His biggest issue is that Sakurai is likely not going to want to have four third-parties. We already know Mega Man is in and Pac-Man is guarantee due to the leak. If guests from previous games return, Sonic will get priority, no ifs, ands or buts. This leaves Snake at the bottom of the totem poll for consideration.
Problem with this is that we won't ever understand the magnitude of difficulty it takes to fit third-party characters. This applied to Sonic and especially Snake in Brawl and because of Sakurai commenting on fitting third-parties as "harder than making the game itself in some ways", this almost certainly applies to Mega Man and Pac-Man for SSB 3DS and Wii U as well. Throw in Sonic into that equation and that's three characters going through the incredibly difficult process of fitting in.
Now try adding Snake to that as well, who had to get disjointed hitboxes in order to fit in Brawl and would be a harder fit than those three? Sakurai has very, very good reasons to be conservative on adding third-parties and I don't think he wants to deal with nightmare of adding four third-party characters and balancing them properly against a 45+ character roster (transformation included).
Unless Sakurai is hell bent on bringing back every single Brawl veteran, Snake is likely not coming back. It's not hard to see why Snake and Toon Link are the easiest cuts to make (although I think Toon Link has a much better chance of getting in).
