Hell, I was really disappointed everytime I finished a cod game like MW,MW2 and Black Ops..
I mean, I really love those campaigns and it's sad when you finish 'em in no time...
Multiplayer is good but I won't stick to it for long, that's sure.
That's why games like infamous,assassin's creed,god of war and uncharted pwn it.
COD + Longer Campagain + Fvcking Unique Multiplayer modes= great success.