Yes, I totally agree that is why we need Nani and Anderson to practice more and more so they can come close to Ronaldo's skill level which is very hard but I thin Nani and Anderson are our only hope taking over Ronaldo's roll. And Ronaldo has 3 years left on his contract I'm hoping he can stay at United all those 3 years.
Its just that when United will miss him, who wouldn't Anderson, Nani, and other youngsters can take the pressure off the manager to get a replacement.