I'd say FuD>5>4>2>3>CE in terms of design. She was oversexualized in Halo 4.
I'm not sure I agree with your order.
It's just that I feel like she gets full blown reconstrucive surgery every game now.
Like, CE was obviously primitive, but I felt like in Halo 2, you could see that being a natural progression from CE. Same thing with 3 from 2. You could see how her original face turned into what was there now.
Then 4 came along and built her up from scratch. Fine, they get a pass, they 343 wants to put their touch on it. Chief got the same treatment.
But now 5 has her looking totally different from 4, and I don't understand why. Why did they redesign her yet again? I know it seems dumb, but it's hard to reattach a character to their past when they don't look how you remember them looking. I can't look at this Cortana and think back to when I scoured High Charity looking for her in desperation. I feel like that must have been a different character.
Also, as dumb as it is, I refuse to believe Cortana will stay evil or be the big bad for long. Simply because of Microsoft's Cortana (aka Siri). I feel like they wouldn't like their voice service being related to a villian.