Poor and recycled map design, little to no character development, absurdly short play time (approx. 1hr 40min of actual play time, lol...), verifiably manipulated multiplayer experience, and zero innovation all point to how shockingly bad this game is. One of these factors alone could put Mw3 in a C tier, but all of them amalgamate to firmly place this game in F/unplayable tier.
Potentially the worst thing about all this is the lack of self-awareness from the creators, Sledgehammer said on Twitter "We’re incredibly proud of Modern Warfare 3." Any self respecting organization will factor customer feedback to iterate on their product. Sledgehammer displays how little they care about the consumer by gaslighting them and simultaneously deceiving themselves into thinking they did something. This is how brands and products get evaporated.
When the company can't even be honest with their fans regarding the fidelity of their product it's time to move on. They are speed running brand degradation