Filing suits against downloaders in a case like this doesn't make legal/financial sense.
It makes sense for MPAA and RIAA to attack random individuals from a larger pool every once in a while as a deterrent.
Given that this is an isolated leak, you can be almost certain that the final downloader is not at risk of litigation here.
I am still not entirely sure they wouldn't. It's not exactly an isolated leak since it's all over the place now. This is a title that they've invested millions of dollars into and I think EA is willing to spend a lot of money on it to let people know they're not just going to get pushed around. Just look at what Valve tried to do with the person that hacked their network and leaked Half-Life 2. I think EA would have no problem going after the initial uploaders along with random US downloaders to set an example to the rest about downloading leaked material like that.