It's not really relevant whether you're old school or new school. This is Pep's school so we should readjust our own expectations both of what types of players we'll sign, and the type of football we'll play, based on what we know of him. We should also, IMO anyway, trust the man. At least for the next 12 months. Clearly we're in for Stones, so whatever your personal opinion of him, making out that he can't defend and that we'd be wasting 50 million on him is IMO short sighted and isn't really giving the lad a chance. Maybe he'll look a better defender in Pep's system than he has at any point previously.
The key thing though is that this isn't a tenuous link to a player we might sign. This is a player we're actively trying to sign who if/when we do sign him will be the cornerstone of our defensive system. So we should look at him through the eyes of our manager and see what qualities he sees.