I find it difficult to definitively slate any new manager, who has no realistic alternative but to walk around in his predecessors hole filled shoes. He's been beset by bad luck. It's not unreasonable to hope a new manager can get more out of some of his players but in the case of Mustafi, Xhaka, Elneney and several others past their sell by date, you cannot polish a turd.
For balance, I'd question his choice to not use Ozil or Ramsey. This seems madness in the current situation and could make the difference between finishing inside or outside the top four. We have them as resources, they're being paid large amounts of money to simply train.