You do realize Halo is the game where you don't even have to be aiming at an enemy to kill him with your AR - a full automatic spray weapon that is proclaimed 'iconic' and that you are forced to start with in the majority of gametypes? COD isn't dumbed down it's just different. I've already had this conversation with HaloGAF. If you really think it's dumbed down, play COD against my friends and I and after we make your butthole disintegrate, tell me again how it takes no skill and has no strategy and is for babies.
I said none of the last sentence other than that it's dumbed down. One to one encounters boil down to who saw whom first, which means the actual killing has little depth. There is strategy in CoD, and it can be intense, although the interaction is purely positional. The meta changes very little, and the design is such that individual skill is truncated in favor of more fast paced action. There is a very small execution barrier involved in the game. You can excel at the game up to a certain point, especially as a team, but because you could beat me (someone who doesn't play it as often as yourself) does not mean it isn't dumbed down. Especially when rewards are divied out for a variety of reasons, sometimes not even relative to what's happening in game.
You cite the example of Halo's automatic weapon; CoD aims for you at the press of a button. Let's not throw stones here.