Have a strong singleplayer campaign that doesn't play like a poor light gun game where you spend more time shooting the same boring targets, following another characterless soldier to the next scripted movie sequence in between. Work out its tone and direction. Po-faced and stupid man-gruff-soldier drama doesn't work when everything that happens is stupidly absurd and and teeming with more testosterone then a He-Man and Man-at-Arms duo cartoon. Lighten up or actually be a bit more compelling in the grimdark. Do something with the engine so there can more complex game modes and level designs, Quake 3 roots are still showing their age. Do something with the multiplayer that either makes it even more absurd and customisable - perks, options and all, or properly balanced. Feature much, much better multiplayer maps that don't focus on the dull horizontal playing field and kill corridors; it's a shame considering how inventive COD map design really was in the past. Feature BLOP's XP levelling system, or something that removes the disgusting grind. [QUOTE="Wasdie"]

CoD 4 was the first FPS I know that truly let you play how you want. You didn't just customize your loadout, but you were able to select perks that could compliment your play style. It's unique.

[/QUOTE] Honestly what comes to mind was Tribes and its loadout system. The interchangeable weapons, packs, grenades, armour and so on was pretty cool. Light classes could vary from flag runners to base disabling ninjas, spotters, harassers snipers and so on with each armour set and variety. No 'perks' so to speak, but pretty distinct customisation and focus on the personalisation. No painting your gun tacticool purple though, with a XxXpR0_sK1llz_hRdS(+)pEXxX weed sig, and a wicked sick skull scope. Nonetheless cosmetics are nice, as hilarious as they are in the recent COD games. Though it really only kicked off in the mainstream post COD4, that's for certain.