I think that there's a difference between playing COD competitively, and playing online. I just don't play COD, I might have the odd game, but I don't go out of my way to play it, not like I will do with BF3. Sorry to make that comparison, but anyway. When I did play Black Ops, it would tend to be co-op split screen, those missions where you have to use stealth, or wipe out an insurgent village etc. I found that to be quite good fun, and not as frustrating as playing online.
Really, I think COD3 ruined COD for me... I really liked the original 2 games, then I got COD3 on xbox and could work out what the hell had happened with it. Running around trying to play online, it was just so badly implimented, jeeps that don't work right... and I could see where the franchise was going, close quarter run-in-with-your-dick-in-hand gameplay, kinda like being forced through a cheese grater, or mincing machine, in a loop.
Now the gameplay has obviously improved and now it's a more viceral game, still close quarters, still being fed into a mincer, but I can see how that's my fault for not playing the game since birth. Thing is, I prefer to play games my own way, and I don't play the way that works well with COD. I play COD and hope not to die too much, I play BF3 and hope not to die! - it's much more difficult for people to completely own you, you can always catch a break, jump in a tank, and there seems to be some good team based gameplay in there if you get into a good server. COD is lacking that, everybody seems to be out for themself - everyone wants to get a nuke or whatever and win the game, who cares about the rest of the team.
I guess COD just doesn't quite gel with me - I prefer my games to be slower paced and more tactical, with a faster paced game like COD, well there has to be balance, and that's missing IMO. If your fighting over a large map, then the faster you respawn the better - you might have a long run before you get near any action, so the quicker you get back onto the battle the better. With a small map, close quarters, well there has to be some sort of balance - a close quarters game with quick respawns is basically a meat grinder, respawn-run-die-respawn-run-die... gets tiresome. If they did something like CounterStrike, say the rounds are quicker, 3 rounds per map and if you die, you are spectating until the next round - add in some reason not to run and die, make people reconsider and think about their next move, make it risky to sit and camp. I'm not saying other FPS games are perfect, but I would say that Counterstrike is a great way to do close quarters, and BF3 is the epiphony of battling over a large area. COD would be one of my favorite games if it just picked a side and stuck to it.
I don't think COD deserves the success it has, because it belittles the efforts that other FPS games make - like Farcry2 - that has some great features, great viceral gameplay that COD fans should love - both long range and close quarters battles, vehicles, a fricken map editor, leatherman surgery, setting fires, great explosives. The single player game is far better than COD's, and probably most MP centric FPS games, it's like story based and free roaming at the same time. Yet, it's about as popular as German dentist - it gets to the point where Farcry3 looks awesome, but it's almost pointless to hold onto any hope for it, a FPS game with a holy-christ-how-epic map editor and kick-ass SP campaign should be the top dog, but because the COD franchise exists, it will never even get close.
So, I guess what I'm saying is COD is over-rated, it detrements the cool stuff that other FPS games try to offer, it stiffles the evolution of it's own genre, and it won't ever change very much, just in case some millions of fanboys get all butt-hurt about it. I'd love to see the next COD game do things differently, not so much bringing a couple of nice visuals to the table, but wipe the table clear and start with the best features of COD and then evolve. Maybe the popularity of BF3 will enforce that, time will tell. I'd love to see the next COD reinvent itself, and tell it's fanboys to either get on with it, or get over it.