I'm against this. If anyone played that train wreck of a game called Trespasser (Jurassic Park), they had a form of it and it added nothing to the game. You actually had to look at your female character's heart tattoo on her briast (no joke) to check your health...gimmicky and unnecessary. As for helmets and view obstructions, we're already restricted from having a realistic view as these games lack the peripheral vision we as humans have. Plus, most helmets, when worn are so close to our eyes, that they rarely obstruct our vision, except for maybe on our periphery, which games rarely incorporate. I think we're already at a disadvantage in a first person view, and adding more clutter, which we normal ignore (like the nose in front of our face) would add very little. The exception might be if there's lots of platforming type puzzles or traps, where focusing on where are feet our in relationship to the hazard would make a difference. I guess I could get behind that.
Ever played a game with descent implentation of first person viewable bodies? I mean Trespasser was a wreck, we all know that + it was made ages ago.
I think I've never played a game with better first person system than Dark Messiah. The combat, the controls, the immersion, everything felt so natural. Being thrown away by a big cyclop, and then crawl to your feet again, all this while you see your characters body entirely, has NEVER felt more satisfying.