That's just the nature of a genre development cycle. Right about now everyone, including the devs, are thinking the same thing.
I predict in the next two years, they're all going to try something different.
EA is already working on Battlefield 3, and I'm confident (at least right now) that they have a design that will feel and look different than BC2. They pretty much have to.
For example, MAG is doing something different and I'm surprised more companies aren't following their lead. But they're all very absorbed in the individual gamer's shooting experience. Screw that. I've headshotted enough people, and called down enough ridiculously over-powered stuff, and shot enough people through walls, I'm not really looking for more of that. MW2 and BC2 are, even in MP, designed to be played solo. Enough solo ******y. Do something that really promotes squad work, and promotes overall team work above finding the best combination/spot to wrack up kill streaks.
I'm looking for the META game. I'm looking for those huge multiplayer battles, where strategy is not where you chose to set your ****ing claymores. I think that's the future of MP FPS gaming, and I think we'd be seeing more of that if CoD 4 hadn't caught on with the masses like ****ing Typhoid.
As it is, we've just been in innovation limbo with FPS for three years. I don't think CoD/BC2 style games are done yet...they will undoubtedly spin off more and cheaper titles to milk it. But I think there's a big shift coming in MP game play, not with this current gen, but definitely after when everyone has gorged on MW2 and BC2-style game play, and simply can't stand anymore.