I personally think Hamilton needs to experience life in another team. I think his attitude, or more specifically his change in attitude during his time at McLaren speaks volumes about both him, and the people around him. It also highlights McLarens failings on driver development. I realise they are hamstrung by sponsorship, but I do feel they should have moved heaven and earth to keep hold of him.
Still, Perez is a great replacement, and if it means Di Resta replaces Massa then I am more than happy.