The problems with Halo 4 were twofold, in a general sense; one, they didn't say enough in regards to the Didact's motives in the game.
The second is that less is more, and a lot of scenes would have played out much nicer had they straight-up cut some dialogue. Cody Miller at HBO posted an edited cutscene from the end of Midnight where they lose Chief's "she told me that once" line to himself, and the scene plays so much better and has a greater sense of subtlety. Cortana stroking the Chief isn't really weird if you know the backstory, and it's not really played that sexually... except Cortana says "I've always wanted to do that", and it pushes it over the edge into weird and creepy for me. A line here and there would have made an inordinate amount of impact on improving the style of Halo 4's storytelling.
(And yeah I think toning down Cortana would have been a smarter move... I'm sure Lorraine McClees who originally designed her was probably pissed with Bungie for inflating her in subsequent games, and she has a point. I also think her more solid representation in 3 and 4 made her "feel" more naked and sexualized than in a game like Halo 2 where she was far more transparent.)
