Seriously, I believe that CoD4 was a good hit, and I really enjoy the game. It brought the good graphics, and started the whole new engine. Now, I think Infinity ward is just getting cheap and throwing crap together. The spawning system is crap, some perks are just plain out stupid (commando), they took out the Model 1337's power, and the maps really aren't too good.
I personally don't like Infinity Ward as they just ignore player feedback. Although, I'm looking forward to CoD6 - It'll hopefully bring a lot more action and crazy "new" gameplay. I think it will be a big hit and that I'll like it, mainly because we have Treyarch developing it.

CoD6 - Awesome.