In an interview with Patrick Bach, DICE's executive producer, over the status of Bad Company 3, he said, "Right now, i would not say we have the bandwidth to do it at the DICE studio in Stockholm. We can always find talented people around the world. The Bad Company Series is by no means killed or anything, its still out there. We merged the main Battlefield game with Bad Company, and we'll continue to do it. I wont say we'll never build another Bad Company game, but right now we're focusing on Battlefield 4."
DICE is currently working on obviously Battlefield 4 but also Star Wars: Battlefront and a new Mirror's Edge so its no surprise that they're backed up but that doesn't mean they cant get a new developer to make Bad Company 3 as Bach said above.
Full story at IGN.com - http://m.ign.com/articles/2013/06/14/e3-2013-dice-has-no-bandwidth-for-battlefield-bad-company-3