We say this because it's always nice to kill with friends but, more importantly we feel, co-op could open things right up and bring a much needed new dynamic to the CoD franchise.
At the moment, Call of Duty single-player is a very linear affair, moving from one check-point to the next through a more or less set route gunning down waves of enemy soldiers along the way.
But think back to that last sweet moment when you managed to create that most coveted of multiplayer experiences; a group of your friends versus a another group or your friends, headsets on, tactics, formations, codenames, inspirational speeches all sorted before hand.
When you don't have the CoD Kids screaming insults down the wire, when you're truly connected to everyone else on your team, no only by network but by soul, you can pull off the most badass military manoeuvres. Flanking, breaching, proper cover systems are all possible and oh so satisfying.
We've tasted it in multiplayer, the same can be done in single-player if only our comrades could come and help us out.
It'd also give developers reason to do away with that linearity. Think about co-op modes in the likes of the Splinter Cell series, where players benefit from going their separate ways, working out pincer movements across different parts of a multi-faceted map and clearing out a room in true Black Ops style.
As far as multiplayer is concerned, the blight of any competitive (and honest) gamer can be neatly stacked under the umbrella of 'exploits',
Basically, it's cheating, somehow gaining an unfair advantage over your opponent to win because you can't match them in skill you big noob... Ahem, sorry.
Here's the problem though: some exploits are mechanical, a way of glitching the system somehow like using a lag switch to make your movements appear erratic to opponents on the other side of the network, or using a rapid-fire controller to plough an impossible amount of bullets into enemies with just a normal squeeze of the trigger.
To those we give a firm and solid middle finger. There's no place for those methods in fair competitive gaming and developers of multiplayer games (and it is a genre-wide problem) should be constantly striving to formulate effective blocks.
The other half of the exploit circle covers little in-game tactics (and these are tactical exploits rather than ones that are more of a hack) that fall in a bit of a grey area.
Although things like camping and drop shooting frustrate a lot of people, the parameters of the game make them possible and some techniques like camping could even be considered wise in certain situations.
It's a debate that'll rage on and, while it's not how we would choose to play, we do respect people's right to mix up their tactics to include some defensive camping. It's the one's that do nothing but camp that annoy, but hey, it's one of the quirks of the game and the best offensive players will be good enough to beat it.
We'd encourage developers to try and minimise the opportunity for tactical exploits in CoD 8 maps, but by all means keep a couple of crevices. Hacks have to be stamped out though. They make everyone feel sad.