They're a few things I'd like to point out:
1) Didn't Kojima say we'll learn what made Liquid Snake the way he was? So far, though, we have yet to learn anything.
2) Some of the screenshots appears to be Middle Eastern looking, and we know that Liquid served in the Middle East.
3) Not to mention, the character with light brown hair appears to have the same hair color, or about the same hair color, as Liquid in MGS1.
4) I also find it funny how the only two shots of him doesn't reveal his face (typical Kojima) lol.
5) In one-shot, however, the character appears to have a strap over the back of his head. I guess it could be an eye patch of some sort, and with Liquid being the only Snake not to used one, well, this could be him using one now.
These are ONLY theories, obviously. Even if it's not a game staring Liquid Snake, maybe he could be a unlockable character or a side-character.
Anyway, how would YOU personally feel about a game with Liquid Snake with gadgets like 007? Yes, 007. Liquid was in MI6 (SIS).