Yeah, it isn't a perfect game, but people make it sound like it's the next Atari ET game. I'm guessing it's because COD sold so many damn copies and gained so much popularity and publicity that people suddenly have to hate it.
The problem is who is publishing it. COD4 was a good game (IMO, I know people will disagree with me here) because it didn't stay to the strict timeframe of one game every year, and thus IW had more time to balance it out before release. From there on, once Activision realized just how well COD4 was received, they just milked the series.
In addition, there weren't many new innovations to the game after COD4. Yeah, a few new perks here and there, but COD still falls into the basic concept of run-and-gun, and each new game only tries to impress you/one-up previous titles with better graphics. Gameplay makes a good game, not graphics.
And yes, you see a lot of COD-bashing on here (myself included at one point, I try to avoid doing so now because it has no actual purpose). People are tired of having the same experience. They want something new. BRINK offers that. BRINK deviates from the simplicity of COD and allows for more complexity. That's what the people here have been wanting for a long time.