I still say Ben Stokes has covered our ass in recent years
The combination of Stokes, Bairstow, Ali, Woakes and to a lesser extent Broad (whose statistcal returns are much better than his flailing Phil Tufnell act would imply) have done so.
But I wonder if that is part of the problem. The top five, Root apart (because his issues are more those of the over confidence of someone who knows he is world class), know they don't have to do it because there is always some other bugger to do so. Even in the bowling, there is a sense that our attack sometimes bowls back of a length to dry up the runs knowing wickets'lll happen eventually. Bairstow's role should be decided by whether the selectors have a youngster in need of batting seven in the side.
So, along the lines of what you said, we have to go back to specialisms. Yes, Stokes at five/six balances our side by allowing us to play five bowlers, but the other four should be selected purely with the acquisition of 20 wickets in mind. That means our best two opening bowlers, our best third seamer to provide variety (ie pace, sharp swing or a left arm angle) and our best spinner.
So a top seven of either:
Cook
An Opener (Stoneman if he makes runs now, if not, the guy who starts the CC season best)
Malan
Root
Stokes
Bairstow
Livingstone
Or:
Cook
Opener
Malan
Root
Bairstow
Stokes
Foakes/Buttler
Then Anderson, Broad/Woakes, one of TRJ/Wood/Footitt/Garton/Willey/Jamie Overton/Mahmood and a spinner. Leach seems to be looking a better pick with every game he is left out, but my personal choice would be his Somerset team mate Bess, who appears absolute quality and has the off spinners advantage of turning the ball away from the plethora of left handers in the international game.