Eric Bana, Nathan Fillion, Dennis Quaid, Viggo Mortensen, etc. = will never be Indiana Jones. You can quote me on that. None of these guys has the charisma Harrison Ford has. They don't have Ford's subtle humor. Those are required for the role.
After this movie they should just stop making Indiana Jones movies. One movie with an older Indy is enough. We don't need to see the continuing adventures of Indy's successor or son either (unless it it done really well, which will never happen). Video/computer games, novels/books, and a well made animated series would be just fine.