Right, and at that point you've had the whole game to bond with him.
Also notice that in Reach, which was a more character driven story, the only Spartan who DOESN'T remove his helmet is Emile, and he's probably the shallowest and the one you care about least. He also won't shut up, so you never have to guess what's on his mind. John, on the other hand, hardly talks at all.
Ironically, I think I would have liked Emile a LOT more if he had never talked. A lot of people complained about how his voice didn't really fit with the character's m.o., and I agree with them, but I was kind of hoping for Emile to be the silent badass of the group. He could have been a more silent warrior, lurking in the shadows, letting his actions do the talking for him. He could have been the Darth Maul of the Halo Universe.
Instead, he was noble's token black guy...and you can't beat Sergeant Johnson on that front.
For me, the trick to doing Chief as the central protagonist while preserving his lack of visage is to play up on the character's mystique, rather than attempting a character driven narrative with him.
The example I like to use a lot is Batman. Not the more recent Batman entries with Christian Bale where Batman recieves a much more in depth character study, but rather the Tim Burton era Michael Keaton films. In the first film, Batman is not really ever given any kind of complex characterization or, or deep introspection. Instead, for most of the film, the character's mystique is played up and he is treated more as a dark shadowy force. In fact, most of the film isn't from his or Bruce Wayne's perspective.
I would approach the chief similarly, as something primal, and powerful. Not big on character...but big on mystique.
Another interesting proposal came from the Halo screenplay that vociferous published on Ascendant Justice a while back (the one I'm making a fanfilm of), and one of the interesting things he did with it was to give the supreme commander of the covenant armada (the arbiter) the most complex characterization in the story.
As he put it, Chief could almost be approached as a slasher from a horror film like Jason, or Michael Myers. From the covenant perspective...he literally is a monster in fact. A demon, as they say.