I think losing Groß would be catastrophic if he was not replaced.I'm slightly concerned by the lack of RB activity, I've been delighted with the rest of the window though. Even if we lose Gross I'm happy with our midfield.
Hürzeler achieved 30 goals and 16 assists from his two central midfield positions last season (Harcel got 19 goals and 16 assists). These players are vital in his system because they do a lot of the heavy lifting in terms of goal creation and finishing. If you take Groß out of our squad, who is going to get rack up the goals or assists from the centre of the park? I think Hinsh and Buonanotte certainly have the potential but they are just so young. Moder and Gilmour have almost non-existent goal and assist stats in the past. You are then left with Milner and Dahoud (assuming Wieffer plays too deep to affect goal scoring stats). I can see why we were linked with KDH, Rutter and Soler.
However, that said, FH is apparently a lot more fluid than RDZ and finds solutions rather than sticking to a rigid formula so if he is happy……