It works for Halo 3: ODST in the way that I think Bungie intended it: to not alienate any of the players who want to see themselves as this rookie (and, thereby, reinforcing the typical FPS space marine power fantasy). Unfortunately, that's a pretty low quality/creativity standard for a narrative device as a whole. For anyone not trying to envision themselves as a space marine, the silent ODST guy strikes a stark contrast against the characters you control that do speak and do have personality. Playing the faceless, voiceless rookie is a strange design decision to make when you have no one to imbue character on you (the blank slate) and when the player is still jumping into the bodies of established characters.

People rag on the silent hero type–and usually I don't agree–but I definitely do in this case. If you look at somebody like Gordon Freeman, the fact that he doesn't speak works because the dialogue of the other characters operates on the level of Greek myth. Odysseus starts out a bad-ass and ends a bad-ass, he doesn't need development; the same is true of Freeman, who even gains nicknames and honorifics just like Greek heroes do in epic meter. “The Rookie” is just an empty conduit for sweet headshots and plasma sticks. Moral is: silence and a lack of character progression works… but for some reason it falls short. Perhaps the isolation and loneliness is the very reason: in order to understand a silent character, other people need to be saying something about him. Or we need to go into the experience knowing more about him than that he's the new guy and he fell asleep in his pod during the opening cutscene.

Also, Firefight squadmate 4 life.