I know what you mean. I'm sure a lot of what I'm about to say would be similar to what many Halo fans felt about Reach, although I don't think it's nearly as bad as what's happened to the CoD franchise, myself.
I loved the original Modern Warfare. It strove to be balanced, fresh and easy to pick up and play. With every annual iteration, the game has become less balanced, less fresh, more frustrating and filled with "stuff", for lack of a better word, with no real thought to what that "stuff" would do to the formula. They basically made a conscious decision to cater to the lowest common denominator, which was a great business decision I guess, but I can't bring myself to play their games anymore as a result.
I stopped here.
As a person who has followed the Call of Duty franchise as passionately and as in much detail as I have with Halo, I can tell you confidently that since CoD 4, only MW2 and WaW have been worse in terms of balance and competitive merit (which is a good determinant of the game's balance).
Black Ops is considered to be, in the eyes of any serious CoD player, the best CoD to date other than CoD 2. MW3 isn't far behind, and even some consider it the best.
CoD 4's "greatness" is a product of nostalgia and (internet) mob mentality.
However, I'm not trying to demean what you have to say or how you personally view the game, I'm just trying to let you know the consensus of the passionate CoD fanbase.