Agreed, think theres some interesting combos there and the spot next to Xhaka certainly up for grabs.That's my only worry, they're all close to being ideal but each is missing one or two crucial attribute which could make the partnership perfect (on paper).
Reckon Wenger realises this but he won't tear up the midfield in one summer. He'll bank on Wilshere picking up some defensive nous, Elneny developing or Ramsey simply returning to his 13/14 self. Not a bad decision imo, the midfield would still be decent even if none of those things happen.
I still have a slight hunch it will be an academy player who complements him the most but of the players already there, I think Wilshere makes the most sense from an offensive POV.