I am just going on the evidence I have so far... I think he may well turn into a very fine player for us, but based on evidence I have on hand so far, I am not betting on it. His physical, technical and mental limitations are worrying for his age, especially in our system with our manager.
Re: price tag judgment - I agree; however, there is opportunity cost to consider. Once we start spending 70, 80+ million, we are running into a limit for us.. but more importantly, you get Xhaka and keep him means you don't get someone else. This has been our biggest issue with keeping so many of our "pretty good" players.