I feel like I've played this before.
Modern Warfare has started to show its age as a franchise in the most recent installment of a normally well-built series. No significant changes were made to weapon sets, overall gameplay, or graphical quality. Pretty much the only change that felt worthy of notice was the addition of Survival mode, and the ending to the campaign carried a bit more weight than previous installments, even if it was slightly anti-climactic at the very end. Even the scenarios for co-op play felt like a watered-down version of Spec Ops mode from Modern Warfare 2.
I sincerely hope that Activision and all other involved parties decide not to go the EA route and make this game every year for the sake of making it. Black Ops out-performed MW3 in sales, a first for Call of Duty. If this game goes back to every couple of years, maybe we can begin to hope for the groundbreaking quality and care put into CoD4: Modern Warfare, but until then... I don't recommend holding your breath.