Never leave home without your shotgun.
Though it's a bit intimidating to look at, it was a good read.
And I don't think we'll ever see S117's face, because he's supposed to be kind of anonymous; the faceless hero of humanity. Even his name, John, is a common-but-strong name evoking the old 'John Smith' title.
For that reason, I'm glad we got to use our MP models as Noble Six. It's easier to explain your various odd actions throughout the campaign when you're playing your own character. My Spartan, Jack-167 is my own little avatar for Halo. My playstyle doesn't fit the usual Hero mentality, so it was nice to have that there.
Though some (or most even) probably don't care about roleplaying in FPS games, but.. it was nice for those that do.