Karl Troedsson, GM of DICE has announced that Battlefield 1943 and Bad Company 2 Onslaught have been cancelled. The reason stated was that the developers can either put effort into these two yet old games or focus towards the upcoming Battlefield 3. I think this move is right as Battlefield 3 is going to be based on Frostbite 2.0 which will feature enhanced DirectX11 graphics on the PC if everything is done right and that's exactly the part where the developers need to pay attention.
Battlefield Bad Company 2 itself used the Frostbite 1.5 engine which was a DirectX 9 based engine but featured great graphics as compared to the Call of Duty series. So let's hope the developers make the right use of this time an d give us a great FPS game.