One of the nifty features of the Halo remake was the ability to run the game with either the original graphical style or high-definition graphics.
Microsoft has apparently filed a patent regarding this type of technology. The patent was filed back in December 2011, after Halo: Combat Evolved Anniversary was released.
It’ll be interesting to see how often Microsoft uses this patent. They do have a remake of the original Fable coming up. I wouldn’t be surprised to see an option that allows players to use HD or original graphics.