He wont be as effective as Ronaldo in front of goal that's for sure. But I honestly cant think of anyone who can potentially bang 30-40 goals per season, possibly Kane is the one can fill Ronaldo shoes. For Neymar, the potential is somewhat there, however his dribbling effectiveness has deteriorated so badly, goalscoring is getting more and more inconsistent. Neymar will be useful for Madrid in the league race but i think if he tries to pull these unnecessary stunts in the CL, it wouldnt work. Madrid aint winning another CL with someone like Neymar.