Hmm, I'm at odds with the 'darker colour palette'. I understand that they may be opting for a storyline which is dark in tone, this is fair enough. However I think this is the wrong way of doing it, for the most part. Some of the most intelligently written and tonally dark entertainment releases ever are vivid in colour. Even in gaming this holds true, Majora's Mask managed to evoke a spectacularly tragic storyline whilst being set in a luscious environment.
I'm worried Halo 4 is doing a different kind of dark, where instead of tragic, emotional and symbolic darkness we're going to get literal, military, gritty dark which was akin to Reach. Don't get me wrong, I enjoyed Reach's campaign but I always got a sense that the story was trying to be a tragedy but...without the tragedy. I much preferred the original, triumphant Trilogy with it's colourful landscapes and regularly upbeat tone. I don't want 343i to forsake the wonderful Halo environments in the name of 'darkness' and not actually reap any kind of benefit because the story's lacking.
I think ODST's art style and colour palette better suited its storyline than Reach did with its own. Hopefully Halo 4 will follow up on that note and do the same. Please don't send us down the overly militaristic route 343i, not again.
Leaves me optimistic. (I am allowed to post that now, right?)