Modric is still there to do what Kroos does but it won't be effective because the physical strength is no longer there and he would not be given as much playing time. Valverde will be the centre of attention, let's see what his performance will be.
In my own opinion, I don't really think he needs much of the physical strength as they will require his emotional support as a senior player in the pitch with them and that's one thing that I know Modrich for. He can help the squad build more confidence in their gameplay to face the opposition. He will also help to stabilize the game at the front especially during tougher matches with bigger teams.