Oh good...
I considered Black Ops' campaign to be the worst in Call of Duty's history...and I thought MoH's was even worse than that.
At least it will look pretty.
Yeah. It'll help a bit because it's a slightly lower resolution, but we're talking nearly negligible compared to 1920x1080.
Look at the BF3 Performance thread. There's several tips for things you can turn down without losing too much image fidelity while keeping everything else on Ultra.
Either way, the game will look great, and it should run at 30 FPS (at the very least) without dips after some tweaking.
If you choose to bite the bullet and drop to 720p I'm fairly sure you'll have no problems with
getting a 60 FPS locked frame rate, but I could be overshooting it.