Who cares if a game copied another game? Enjoy it and stay, or just don't buy it. Many games had the same features as CoD, but as soon as Halo takes a crack at it, it's unacceptable... Battlefield and Crysis both had perks, Crysis had killcams, many other games have ADS, many other games uses the flinch mechanic, etc. But as soon as Halo implements some of these ideas, it's copying....
Plus most of them aren't even copy and paste, so to what degree does a game count as copying another one? "Oh no they made a short, medium and long range weapon category, they're copying CoD" It's plainly stupid and arbitrary.
Every FPS game copied the original Wolfenstine, end of story.