CoD4 had a 4 hour campaign, and yet the only game on PS3 I've played more than it is Oblivion. I've clocked at least 30 hours, and I only stopped when I got a new game.
A standard FPS focuses on multiplayer. Single player is of secondary importance. Quality in the campaign is more important than quality. This is the same for Halo 3, CoD4, and pretty much every FPS of the last six years.
And now, your comment about paying for graphics...sigh. That's all I have to say.
Do people buy Gears 2 for graphics? Because the campaign is certainly no longer than ten hours.
Did 9 million people buy Halo 3 for the graphics? The graphics weren't even good.
So please, don't judge the quality of a game until you have played it. Find me one review not from a porn magazine that says that the game is nothing but a graphical powergouse.
(Former) Lead Moderator and (Eternal) VGC Detective 
