It looks like development, or at least management of the next Battlefield game has already started! DICE design director Dan Vaderlind tweeted (https://twitter.com/mrVaderdan/status/675317213302247426) that now that Battlefront has shipped, he is onto his next project, which will be "the next Battlefield.
So here is the million dollar question. If this Battlefield 5? Bad Company 3, or Battlefield 2143