I think KP was very poorly treated by England (particularly in the summer) but his time has gone now. There are still big holes in the England team though. No second opener, Bell has been poor for some time and hasn't got a good record at number 3, Bairstow has yet to cement his place as either keeper or batsman, Stokes is hit and miss (though obviously worth persisting with) and the current crop of spinners aren't even as good as Ashley Giles, who at least kept runs tight.
A pasting in South Africa wouldn't be a shock. The conditions will suit our team more but they're much better than us.