I think the team will play better (even if only for a while) just for Benitez leaving, regardless of who replaces him. That's why I would rather hope he stays.
What Real Madrid really need is to get rid of the dictator Perez and all the ego's in the squad.
A lot of People view of Madrid is that of the galactico's till now but in the 90's with Sanz I respected them way more than since Perez' took over.
Don't really see who they can get in the future that they haven't already hired and fired. Maybe Mendes will drop Vila boas in the seat. Emery would be hilarious though. It needs to happen.
Zidane is zidane, he will drop cristiano or james or whoever big name isn't playing well and they won't be able to talk back because it's zidane.
That means they may improve considerably. Let's hope he's a shit manager.