I recall a looong time ago someone posted that version of Snake in this thread, but added a beard on him and gave him the mullet. That's my ideal Snake, ballistic vest and the iconic beard.
Solid Snake never had a beard as part of his image. It was either a stubble like in MGS2 or the mustache in MGS4.
Solidus and Naked Snake/Big Boss were the ones with beards as part of their image. Big Boss started it while Solidus was the perfect clone so, he imitated everything to look like him.
Liquid's iconic image is blond, long, and luscious hair, awesome pecs, and his overcoat.
Snake in Brawl despite being called Solid Snake is more like a fusion of both Naked and Solid since Solid wore the suit while Naked made the "yum" noises, had the beard, and the palette swaps that were based on his camouflage in MGS3.
Personally, MGS1 - cropped hair, ballistics vest, and no beard - or MGS2 Solid Snake - mullet, no ballistics vest, and stubble - would be the most iconic followed by MGS4 because that's a departure of Snake being incredibly old and it makes people feel sad even if he has a cool suit. Or we could go with MG Snake in his fatigues which isn't well-known, but could serve as another alt.
That said, if Big Boss made it in instead, then either Peace Walker - MSF Sneaking Suit or fatigues - or MGS3 - prototype suit or Tiger Stripe fatigues with or without the bandanna - Naked Snake since those are the least "graphic" games of the series. The issue is that it would cause some confusion to players on which Snake is it. Sure, The Phantom Pain Big Boss could work, but I doubt Nintendo would allow it since he has a protruding shrapnel on his head and scars. Now, Big Boss with the overcoat would work fine except the issue with reputation since most people are used to seeing either Solid Snake or Naked Snake/Big Boss before he's a senior.
I agree. That would be amazing, since his best suit was his MGS1 Suit, but his best hair was the mullet and beard. The only other thing I would want is that Sakurai removes the slouch he had in Brawl. I want Snake to stand at full height.
Why not just have a separate alt. Big Boss, that way we have both?
Solid Snake and Big Boss always slouched in their games. Same thing with Raiden pre-Rising. Heck, even Sam Fisher and the Assassins from Assassin's Creed slouched. I think it's a way to lower their appearance since they're trying to sneak around along with the fact they're all tall so, being "shorter" is probably more helpful when they're trying to not get caught and not getting shot by snipers.
In a fighting game, slouching means they have a smaller hitbox. Ganondorf and Bowser stand upright and they're huge targets compared to Brawl Wolf who was almost crouching and Ike who's slightly scrunched in. Wait... is Ike slightly shorter than Marth because he's slouching?