Even though I still own and play MW1, MW2, WaW, and BO2, I've given up on the COD series. I know they changed up some features in COD, but sometime about it doesn't make me stay interested in COD. With BF3 released back in 2011, I still play the hell out of it and don't get bored.
If I ever consider buying another COD, they would have to completely change up the usual formula.
I have BF4 preordered for the PS3 since many of my friends are not getting the PS4. For the X1, I'm buying it digitally since I don't see myself getting rid of this game at all.