Alright here is the side that competes with any other Test side
Watling/Flynn
McCullum
Brownlie
Taylor
Ryder
Williamson
Ronchi
Vettori
Southee
Bracewell
Boult
Problem is getting most of them on the park for starters.
I wouldn't have McCullum opening in an ideal world but there is no room in the middle order, and plus averaging mid to high 30's as an opener for a NZer is actually really good.
I'd also consider interchanging Ryder and Brownlie.
The main problem with this side is it's a bit light on bowling so guys like Ryder and Williamson would have to fill almost 15 overs in a day, I think Ryder is good enough to fill a 4th seamer spot but his injury history is a bit of a concern with his bowling. I hope we can get something like this side on the park against England, imo it's a pretty damn good side.