I have to say I too wonder about Bairstow's place in the short term - and I'm a huge supporter of the lad. The thing is, since that South Africa game last year, he has spent so much time as a glorified drinks waiter because of the "no risk of injury" England system, that he seems to have gone backwards as a batsman - he was always a bit bottom handed but he was much freer with it and played straight defensively. He may be one who needs a year back in County cricket to come again.
As for the balance of the side, I have to say that I would prefer to see five bowlers in there, whether through a Watson like relief bowler such as Ben Stokes or through Bresnan batting seven. Whether it would materially improve the side is debateable, but I think it would go some way to doing so, and to taking stress of Anderson's aching joints as well!