there isn't an Face to connect with the Call of Duty name. Nintendo has done this the best and has matched an face for all there franchise's such as Mario, Donkey Kong, Zelda/Link etc are the reason why those games have ran for as much as 25 years.
Call of duty might be the biggest games of this gen but they have no face. An Game could come out and be exactly like COD but better and could attach the crowds and COD will die. While many have failed at that there will be one since there are always someone trying to take down the best. And an Name like Call of Duty wont make it last.
One thing Activison should of done is make an playable character like Soap be the face the Call of Duty in all its titles from MW and with that build an character. But since they haven't and its getting too late now it wont be long before we will get the guitar hero repeat where people will soon just stay with the last game instead of doing an minor upgrade with the next title. Also like Guitar hero due to the yearly cycle the games will lose its luster and it wont be the cool game all the gamers must buy.
I find it funny because Guitar Hero and Tony Hawk are Activison titles that have suffered the game type of effect of the yearly cycle. I believe Activison know that COD wont last so they are going to quickly install pay to play online and 2 games a year cycle and bleed every last cent out of the COD name.
Of Course That's Just My Opinion, I Could Be Wrong