The curse of live action fictional entertainment. When someone does something awful, grows out of the role, has a contract dispute, is injured, dies - producers and writers are up a creek. Do you do the CGI Luke Skywalker thing? Do you kill the character? Make a woo woo body switching plot? Find a look alike? Every solution will feel shoehorned in and inauthentic, and for every fan who's back you scratch, you're gonna enrage three other groups. Thankless fucked position from management's end.
With animated or cgi stuff, the only real issue you have is finding a convincing voice double, which, while tricky in it's own right, is much more feasible than like...finding an Elliot Page doppelganger on the street or whatever. If we weren't collectively as a species veering into AI, I'd like to think that we'd be balls deep in cloning, so that every elite Hollywood star would have four 1:1 twins that can just be phased in and out as the situation rises. That'd be neat. >>