While precisely no one at Old Trafford will be sorry to see Jurgen Klopp go – the prospect of Liverpool suffering a decline like Manchester United’s post-Sir Alex Ferguson is a tasty one indeed – the likely arrival of Arne Slot in the Anfield dugout will present a new set of challenges for the Red Devils. And not just because Slot is one of the sharpest tactical minds in European football. The job he has done at Feyenoord – Eredivisie champions for only the second time in the 21st century under him – is somewhat similar to the one Klopp did at Dortmund, triumphing over more traditionally succe…