It does not matter if certain gameplay aspects have existed in earlier titles, having all that stuff in one game is what makes it like cod. Not to mention the way it is implemented is similar. The Hit markers, unlimited sprint, white text points that pop up in the middle of the screen that tell you how awesome you are every time you hit a vehicle once and someone else blows it up. Kill steaks, point based scoring, loadouts and so on. The whole points in the middle of the screen thing every time you kill someone or do something would have been enough to cry foul for me, but it just brings it all together. And it is bringing all of this stuff together and wrapping it up in a package that looks like cod is what makes people think it is like cod.
It may not play like cod, but it certainly looks it. And imo, Reach plays too much like cod for me tastes (compared to 3) and 4 only introduces more cod-like elements, so I don't see how this helps the issue.