Which is why the more recent H2 Anniversary cutscenes re-emphasized that no, she's not naked in H2. She has a body suit. (see pictures above). The question storywise is whether Halo 3 is closer to 'nakedness' (as between H2 and H4), or if the combination of game geometry and visual patterns still imply bodysuit (I propose yes due to the collar pattern). If 343 ever does a Halo 3 rendered cinematic with highly detailed visuals like H2:A's cinematics, then we'd find out for sure. But Halo 4 is clear - no collar, or open collar, and definitely more like body paint than a skintight bodysuit.

Anyway, again, this was in response to the comment "she's naked". Actually, she isn't. Definitely not before 3, and unlikely in 3; much closer to it in 4 however.