While he makes a decent point about any game that's popular (or anything in general) is going to get a lot of criticism and outright hate, you can't actually DO much with a game like Call of Duty that'll be considered fresh and imaginative. It's always going to be a war game based vaguely on an actual war or an imaginary one. It's going to get attacked a lot if it doesn't change and continues to get praised as a ground breaking and fantastic game. Updated game play, controls and an addition of multiplayer don't necessarily make a game shiny, great and perfect; it might make it more fun to play at best.
Also the article is equating fun gameplay to a good game; That is utter bs. Call of Duty might be fun to play (I'm a fan of multiplayer on World at War) but does it actually make the game good? I think that gets lost in translation with a lot of the die hard fans and the critics.
So really, the article makes good points but he fails to take into account that CoD can't really change much past it's traditional formula and story, and that's the most legitimate criticism a lot of people (including myself) have of it. It's fun, but it's not as great as it's made out to be either.
Okay, think about it this way. The games are about war. At this point in time, there are SO many people sick of wars and political conflicts in real life... why would we want to play it in our down time? I personally can't stand war games. They just make me think of real people dying on the other side of the world. When I play games, I want an escape, not a constant reminder of how crappy our world is getting.
Than you get into the fact that Call of Duty's popularity has caused a HUGE amount of copycats and shooters to take over the game marketplace. The games are not terribly imaginative. Like it or not, there's only so many ways you can point and shoot other soldiers.
It's more about the fact that there are SO SO many better games that deserve the accolades CoD always gets, but doesn't deserve. They are somewhat brainless, shooting games, that are for the most part just reskins of the previous games.