I find it funny how the trend in most of these comments is "CoD is getting worse. MW2 was good, but BlOps failed!". MW2 was the biggest heap of trash to hit the shelves. The multiplayer was imbalanced, the maps were terrible, and the service was shit. Then to go and say that Blops was terrible? You're joking right? Blops honestly, was a good step back to CoD4 in terms of multiplayer. The maps weren't completely balanced, the guns were so-so, but the perks were basically spot on. The basic judgement coming from these comments isn't from actual competitive multiplayer outlook, it's by general fun. Of course you're going to get bored of a series of games if they're just releasing new guns and maps and you play it every day, especially when you're not used to them, or you don't like them. A good example would be when they released Overgrown and Crash for MW2. The community went into a frenzy because of how epic it was to play CoD4 maps again. I still play CoD4, solely because it's everything I like in an FPS, and because the community is still strong, and the game is more balanced then any other FPS I play. Not to mention the competition is a lot stronger in CoD4 then any other of the series.
A lot of the time you will pass judgement on something because you are used to something, and you don't like the change, whether it be logical or illogical, or better or worse. Either way, it's their job to release games, and by continuing their AWARD WINNING SERIES, I'd honestly say they are in the right mind set. The multiplayer may be just alright, but their campaigns are generally a good run through.