It's fine to have a Roy or Bairstow or Buttler coming in at six in your Test team. An aggressive shot-maker who can potentially build upon a platform that your top order have built, and demoralize and put away the opposition.
It's just about defensible to have two, if one of them can don the gloves and bat seven.
To have three - especially when you've got massive questions about the capability of the rest of your top four - is just suicidal.
I can see why they tried Roy. His one-day batting showed that he has the temperament and the shot-making talent for international cricket. But this series has clearly shown that he lacks the technique and the patience for Test match cricket - unless he's going to play as the solo slogger at #6. We simply can't afford the luxury of playing him and Buttler in the same side against a competent attack (as New Zealand and South Africa, even without Steyn, will be this winter).
Denly - as hard as he's battled this summer - just isn't good enough either. His two fifties showed plenty of character - but even they required absolute bags of luck to last even as long as he did. Just not enough talent.
So we need to find two new batsmen to join the top five alongside Burns, Root & Stokes. And if they're going to be ready for the next Ashes, we should be starting by blooding new faces now.