The “Halo” series is known for its religious symbolism. For example: The Ark, the Flood, talk of salvation, sins, and heretics.
I don’t like Cortana’s appearance in Halo 5…
…but I read a fan’s theory that made me feel better about it (I call it the “Eve Theory”):
Cortana is like Eve in the Garden of Eden. Her nudity is a symbol of her innocence. When Cortana “eats the fruit from the Tree of Knowledge of Good and Evil” — i.e., when Cortana touches the Domain and gains access to all the Forerunner’s knowledge (knowledge that, I’ve heard, might be corrupt, too) — she loses her innocence and, like Eve, clothes herself.
There is one, for lack of a better word, problem though with this way of looking at Cortana’s appearance:
Eve clothed herself because she *needed* to (to hide herself from Adam), and Cortana clothed herself because she *chose* to. So, in that way, Cortana isn’t like Eve.