One piece of information released was the length of the campaign; when asked about the length Goldfarb responded, "It’s not Skyrim, but it’s not three hours, or anything like that... Based on our play-times it’s probably more than that [of Modern Warfare 2's], but it’s not twice as long. But, again, we’ll see. When you play it on hard difficulty, it’ll take a lot more time.
Long story short; the game could be anywhere from 3 to 12 hours long, with the actual figure probably being closer to the latter. Furthermore, the plot is said to gradually gain in pace; with the earlier missions, such as those shown in Faultlines, having a slow pace, as opposed to the final missions which are "worth the wait."
— Goldfarb on the plot distinctions between Bad Company 2 and Battlefield 3
Also, unlike Bad Company 2, which essentially flew players all across the world, Battlefield 3 won't be set in as many locations in an effort to make the game seem more realistic, and will feature a much more serious story; one which Goldfarb himself admits may scare those who fell in love with Bad Company's humorous side.