Calls for Bairstow to move up the order are only going to get louder.
England could bring Ballance in for Vince, but will be wary of having yet another southpaw in the batting line-up given Lyon's effectiveness. I suspect Vince's 83 will give him another chance in Perth, although given England's record there, he's probably on a hiding to nothing.
It's not just Joe, it's the whole side that has trouble converting (Cook used to be an awful lot better than now as well). Looking at the stats since the start of 2014 (when the current England era arguably began, after so many retirements post 2013 Ashes), England have one of the worst ratio of 100s to matches played of any team (only West Indies and Bangladesh are lower), and one of the worst conversion rates of 50s to 100s as well (worst of all the top 8 teams, only Bangladesh and Zimbabwe are lower). But their rate of scoring 50s but not converting them is higher than any other team in the period, and their overall rate of 50+ scores (50s and 100s) per game is about equal to the other top teams - Australia, India and Pakistan, and better than South Africa.
http://stats.espncricinfo.com/ci/engine ... pe=battingThat's very telling, IMO. This current batting generation just doesn't seem to have the concentration to grind out the big scores on a regular basis like the players from India, Australia and Pakistan do, and like England used to when Gooch was the batting coach and the lineup featured Strauss, Trott, KP & Bell. South Africa also seem to have fallen off on that count since the loss of Kallis and Amla's drop in form.