You guys forget that CoD is reviewed and played as a mainly MP game. So while their campaigns have not pleased everyone, it's the MP that draws in such large numbers.
I've been a huge CoD fan since the first CoD, I've bought and played them all. You can clearly see that the MP has evolved and changed over the course of the years, but not in the leaps and bounds that you will see in a SP franchise (Mass Effect, Dragon Age, The Witcher etc...). The same has been true for Battlefield for years only people don't hate on BF as much as CoD is just so much bigger, and it's always "cool" to hate on mainstream things.
Ghosts has been a wake-up call for most CoD fans though. There are only so many ways one can innovate shooting someone in the face, what CoD desperately needed was a new graphics engine and more interactivity with the map.
Activision are greedy bastards that won't invest in creating a next-gen engine, they'd rather stick to the same old shitty engine that started showing it's age with MW3 already. The "interactive destruction" in Ghosts was really needed, only it wasn't expanded upon properly and therefore fell flat on it's face.
The next CoD from Treyarch will be the CoD that makes or breaks the franchise. Treyarch have been releasing the better CoD since Black Ops. Infinity Ward are a shell of their former selves after the MW2 saga.
