I'd like to preface this by saying since the last time this came up I've seen the H2A and H5 cutscenes, and they are going for a dressed look-- now. I reject the idea that that overwrites or invalidates how she looked before, especially since she didn't look dressed in Halo 4 or H1A.

: Uh, is your only evidence that she's not 100% completely nude the fact that
: her belly button indent is a little more than a typical physical
: bodysuit?

Her butt is probably also evidence, but with that you could say it's just kind of wedged up in there. How form-fitting a bodysuit is was a sticking point previously, and it's painfully obvious to me from some depictions that there's no covering.

: ... still not convinced. She has no lady bits. Not nude. But certainly nude-like.

I keep hearing there were nipples in Halo 3; I can't seem to remember a time I saw them clearly, so I won't say it's definitely true. What else is there? Well, she has no visible labia. That still does not mean a lack of nudity, as many people could tell you. There's also no slit or divot in her nether-regions. I think they never had that firstly because Microsoft would flip out and ratings boards would classify it was adult or refuse classification (which means not allowing it to be sold), and secondly because until the last game or two it wasn't really possible to have it be as subtle as it would be in a real female form (especially with how small Cortana usually is).

: I did not bring that up at all in this thread, it is completely irrelevant to
: what I'm talking about here, which is her objective appearance.

That's the point. I don't think you are talking about the objective appearance, I think it's your subjective interpretation of the appearance. I think the way you view it is clouding your view of what it objectively is and was, and what it was intended to be.