After I played Call of Duty, I couldn't stand any FPS that didn’t have iron sights aiming and the ability to go prone. After playing Medal of Honor, I can't accept any FPS that doesn't have peek-and-lean action. And after playing Battlefield, I insist that every FPS have a more open-world, free-roaming feel to the campaign levels, instead of guiding you through what is basically a narrow path of playable space with every alternate route conveniently blocked off with debris in a transparent attempt to give the illusion of a larger map.
At the end of the day, I'm not really satisfied with any one of these shooters.
COD and MoH both have really restrictive campaign modes, and in BF you can't go prone. (What the hell is that all about anyway? Maybe they changed it in one of the newer ones.) Neither COD nor BF have peak-and-lean, which adds a whole new realistic feel to using cover. And all three have WAY too many cutscenes/cinematic semi-playable things. I'm sick of those games trying to be like an action movie. Slow motion breaching is cool, I guess, but everything else is dumb and has zero replay value because you know it's coming.
I'm also sick of all the vehicle missions—minus the BF free roaming level, which is very reminiscent of the awesome Halo vehicle gameplay. Why can't the vehicles and the sniping be weaved into the regular gameplay as possible strategies (like Halo) instead of having "the sniping mission" or "the tank mission"? Tanks, helicopters, and sniping are all cool, but removing them from the normal gameplay results in really boring, predictable levels where the computer walks you through the exact same sequence every time you play. Plus, a game will only have the one tank level for example, and so you get this really half-assed gameplay that can only be fun because, Woah! I'm, like, in a fuckin' tank now for some reason! –Even though for the rest of the game you're doing something completely different.
Probably these games are so flawed because most people only buy them for the online multiplayer, but I would like to see these modern warfare-style shooters take a page out of Bungie's book and develop campaigns that are actually worth playing through more than once.