Re: not contributing much when the goals dry up, he's already got 7 PL assists this season. Compare that to the other big scorers (in order of PL goals scored);
Kane 1
Salah 7
Aguero 5
Sterling 6
Vardy 1
Firmino 6
Lukaku 5
Hazard 2
Morata 5
Rooney 2
Martial 4
Lacazette 3
Mahrez 7
Son 4
Sanchez 3
Jesus 2
Murray 0
De Bruyne 14
He gets more assists (tied with Mahrez) than the top 17 goal scorers in the league until we get to De Bruyne in 18th place.
So apart from scoring a bucketload, assisting a bucketload, constantly occupying multiple defenders freeing up space for his teammates, stopping opposition teams playing a high line because they can't handle his pace and hence leaving opposition midfields more isolated and generally being fucking good at football, I guess he doesn't contribute too much.