While this seems like a thread of 'wake up you sheeple, why can't you notice things like me?' I think it's a bit childish to just call a series you don't enjoy over-rated.
But, i'll participate and attempt to take a slightly unbiased approach. The series I enjoy the least and think is 'over-rated' would have to be Call of Duty as well, but for more clear reasons.
1. The same game engine, 6 games in a row.
This is what allows Activision to churn out a game every year. They have the security in knowing that they are going to break record sales on a yearly basis, why should they show ingenuity? They don't need to and probably never will.
2. They lucked out on being the 'Cool FPS'
Call of Duty has essentially taken the success of Halo this generation and now has the spot as the FPS everyone plays.
The fact that there's also a schoolyard mentality helps their sales, kids in school who don't play COD aren't cool.
3. Developers gonna develop
As mad as everyone may be about the yearly game, it is just another game. And you can't argue that Activision/Treyarch/Infinity Ward are not successful at publishing/developing games. They obviously are doing their job right and not everyone is in the business to be 'indie' or have artistic expressions through their games.
4. Why do I care?
I don't really. I just felt like making words, i'm not mad and I still play Call of Duty with my friends occasionally but I won't continue to buy them. In the end it's just another game you like or you don't.