I read that Paul's Grandfather was added to the script, because they didn't think that the Beatles could carry a movie on their own.
If that hadn't happened, how different do you think the movie would have been?
I think the grandfather was just suppose to be another subplot for the film to create conflict, i.e. manipulating Ringo and him disappearing. I think the movie would have gone mostly the same way even if he had he not been in it.
shareIt wouldn't have been quite as funny. Wilfrid Brambell was a great comedy actor and his presence greatly added to it.
shareIf they hadn't had Grandfather in the film, they would have had to include another slightly antagonistic character.
This is something the Marx Brothers had realized many years earlier, that comedy with a rough edge works much better if it's directed at someone established as unsympathetic. Not that the comedy in this film had much of an edge, but the Beatles are snarky kids who make fun of everything, and it wouldn't have been as funny if they were just telling people who were there just doing their jobs "You're a swine". No, for the Beatles sort of humor to work they needed someone who needed snarking at, and as such, Grandad was a stroke of genius! He was temporarily embedded in their lives but they had no power over him, and he started the bitching himself.