Ballance has had a bad series but in the WI he managed to reach 1000 runs in one of the fastest times ever. A bad run since then but I don't think his place should be under threat, although he will have work to do in the Ashes. Main concern would be Bell, whose poor run extends rather longer; and Ali, who looks like he has potential in the long run to be fair.
Also Stokes' bowling is a bit temperamental, but I expect he's going to be one of those people capable of producing the occasional destructive spell, so not really a concern. But despite the loss, we look in better shape now than a couple of months back.