5. Overhauled Perk system
In principle, we're not sure we want to see Treyarch and Infinity Ward's game become any more alike. But in practise, Black Ops 2's Pick 10 system worked surprisingly well, allowing a degree of freedom and creativity rather than funnelling players into the same old loadouts. Sure, a few majorly irritating knife-focussed builds have sprung up - but it's not as if we've never fallen foul of knifemen in the Modern Warfare games. Obviously, Infinity Ward wouldn't want to be seen to be copying their sister studio, but they could cleverly disguise it. The Choose 11 system, for instance. Or the Grab 12.
6. Better stealth
We're really very sorry, Modern Warfare, but there's something you should know. Crouch-walking after an NPC companion with "Follow" hovering above their head isn't stealth. Yes, All Ghillied Up was an excellent, atmospheric journey through irradiated Pripyat, but we do wish you'd stop trying to reuse its insta-fail stealth systems in every game. Actual stealth involves things like sightlines, audible ranges, inquisitive enemies with - and we're sorry to bring this up again - actual AI. Implemented properly, it can make regular combat more interesting too. Just try it, please. You won't go back.
7. No more respawning enemies
Oh Modern Warfare, you promised you'd stop this. And in Modern Warfare 2, you delivered. Spawns were ultimately finite, though we're still a bit suspicious about the number of gang members able to squeeze themselves into that favela. Modern Warfare 3, however, saw a return to this nasty, outdated battle tactic, in which enemy troops indefinitely teleport in from some magical Russian conscript dimension till the player crosses an invisible line. To be honest, we're not too fond of spawns even when they're finite - it's an imaginatively lazy way to repopulate a battlefield. Halo: Combat Evolved made use of dropships 12 years ago. It's time that Modern Warfare's reinforcements were better integrated into its world.
8. Better story
The Modern Warfare trilogy storyline is a mess, frankly, at its bloated incoherent worst in Modern Warfare 2, and still not genuinely good by the time of Modern Warfare 3, despite plenty of time spent tying up (and then killing) loose ends. COD is all about bombast, we get that, but perhaps the narrative focus this time could actually be the soldiers themselves, rather than the political machinations happening off-screen. We'd suggest getting a professional writer to help, but Treyarch hired Dave S. Goyer and look how that turned out.
9. More actual Modern Warfare
There was something weirdly unsettling about Call Of Duty 4's campaign, it's not-quite-ripped from the headlines Middle Eastern levels combining with scenes such as the nuclear detonation and the AC-130 sequence to form an inauthentic, but somehow troubling depiction of the nastiness of modern conflict. Then it all went a bit Red Dawn, and any slightly unsettling parallels with reality were junked in favour of ridiculous imagery of the Eiffel Tower falling down and other, attention-grabbing shock scenes. We'd like a return to the first game's (relative) groundedness. It might have come about purely by accident, for all we know, but it was certainly more affecting, and seemed to question hoo-rah jingoism in a series that nowadays prefers to celebrate it.
10. New engine
This isn't just a fancy way of saying "better graphics", though we'll admit that's part of the issue. Infinity Ward's IW engine has been powering COD for some time, though Treyarch and Infinity Ward technically use different variations of the software. It's held up admirably, delivering the smooth, 60 fps feel for which the series is famous. But maybe, just maybe, it's time for an upgrade. Physics is one area that badly needs to be worked on - Battlefield's destructibility makes COD's environments feel laughably artificial by contrast. There's a good chance that Modern Warfare 4 is going to end up straddling hardware generations like a camouflaged colossus, so it seems an appropriate time to experiment with the engine at its heart.
Still playing the latest Call of Duty? Here are some Black Ops 2 Zombie Mode tips.