I've noticed a number of aesthetic changes of Elites in Halo 4 that seem a bit...off.
Below is the best picture I've found thus far of an elite in H4. I suppose he is in a combat stance, but he seems so much more hunched over than elites ever really are. His skin is incredibly leathery and almost scaly in places. Granted the developments in graphics allow more detail but still it would not have been too large of a task in previous games, and I have yet to read any description that states elites are scaled. A second point is the mouth. There are the usual 4 mandibles but none of them seem to be teethed. Thirdly, it seems to be much thicker. He clearly has bulky, heavy body armor but what you can see of his exposed legs and torso, he looks proportionately bigger, sans the arms.
Now here are elites from Halo 1,2, and 3, which I used for comparison. Interesting changes throughout but I still think this is one of the largest changes throughout the Halo series in the Sangheli.
Feel free to make any additions to changes that you've noticed as well. Actually, please do.