Played through most of the single player. The gameplay is extremely linear. COD games have always been like that, but with COD4, you didn't really notice because the levels were well designed and the objectives varied. Now in Codblops (COD7) all the levels are pretty much the same. The graphics are OK, but I wouldn't say they are any better than COD6, which was also extremely disappointing. Multiplayer can make up for these shortcomings, but with no independent dedicated servers that allow all types of modding / customization, that's really a no-go there as well (though better than COD6).
COD4 is still my favorite FPS game in the past 5+ years and I still play it once or twice a week. I'd love to get behind another incarnation of the series, but they keep making terrible games. Its not for lack of time / money, its just the top level design decisions that are ruining them. I own COD1, 2, 4, and 5. Hopefully 8 will be better so I can buy that too.