Xhaka at 35m was a huge deal at the time. Aboomerang, a genuine World class player and forward in his prime didn't cost much more a couple of years later.
Yeah I'd happily ship all of Xhaka, Ozil and Mustafi off the wage bill and bring in one CB. Then just hope the big young Greek (terrible and big injuries this season)steps up next year as well as Emile Smith Rowe. Both of those look to have serious talent and worth gambling on if they can be fit for pre season