COD4 is great fun - but for real skill it needs a lot of tweaking - so that you can play hardcore mode - so that theres a fair degree of acc. on the first 1-3 rounds or so but a lot of spread/recoil after that - to keep people from spamming to get kills with the high damage.
Last time I played servers either seemed to be low damage so you had to spam forever to get kills and it came down to a mixture of luck or who had the best internet connection, or high damage/hardcore but too much accuracy on the guns so someone could just spam the area enemy were likely to be and get a load of kills.