i have recently purchased h4 goty and changed my armor and it is still stuck as my old look i dont know why it wont change. thanks 
Have you had a chance to check out the Halo 4 FAQ yet?
I changed my armor but my Spartan on Halo Waypoint hasn’t updated. Why?
4GB consoles: Halo 4 uses the hard drive to cache and store the altered image and save that image to our services used by Waypoint to display the update. Unfortunately without a hard drive, this update process does not occur.
If you do not have a 4GB console and are still experiencing this issue, make sure you are changing your Spartan armor in the main lobby and not during the search phase.