Quite interesting. Xgrayninja posts in the IGN Boards what he claims are snippets of an interview between Gamepro and Hideo Kojima, but we can't seem to find the said interview at GamePro (exclusive to the GamePro mag, maybe?). According to one snippet, the centerfold-quality "back-to-the-wall" stealth pose Snake pulls in prior outings is gone. Hideo, elaborates:
(The signature Snake pose) rarely happens on the battlefield. Nobody is cool enough to hide like that. By eliminating this move, it's more like real life. Snake can hide behind something, then sneak a peek and shoot. There are more actions to it, and it's smoother that way.