1) It would be a huge mistake to remake the movie. It's too much of a cultural icon to tamper with.
2) It would be impossible for anyone to play Don Corleone without everyone instantly comparing him to Brando. Marlin Brando transformed himself into Vito Corleone. It's one of those performances where you forget the actor, and the actor completely becomes the character. I have the same reaction to Al Pacino in "Scarface". A complete transformation. (Interesting trivia: the studio wanted to give Danny Thomas the role of Vito Corleone).
3). If there were another Mafia movie made that required a heavyweight character like Vito Corleone, Al Pacino would be the first obvious choice, but he couldn't do it, as his past roles would interfere. Robert DeNiro is not a very multi-dimensional actor, and this role would require dimension. Ray Liotta is not a very good actor. Joe Pesci's voice is too high, and he's too short. He could maybe play Little Nicki Scarfo (the NJ mob boss from the 1980's).
Now, I'll try from memory to cite the dinner scene with Tom Hagan and movie producer Woltz.
Woltz: "Why didn't you tell me you worked for the don, Tom? I thought you were some two-bit hood Johnny Fontaine was running to try to muscle me."
Tom Hagan: "I don't like to use his name unless it's necessary. Now the don is Johnny Fontaine's godfather, and to the Italian people that's a very religious and sacred ____."
Woltz: "Tell the don he should just ask for anything else, this is one favor I can't offer him."
Tom Hagan: "The don never asks for a second favor when he's be refused a first, understood?."
Woltz: "You don't understand. That part is perfect for him. It would make him a big star. And I'm gonna run him out of the business, and let me tell you why.
Johnny Fontaine ruined one of Woltz International's most valuable proteges. For five years we had her under acting lessons, dancing lessons, singing lessons. I spent hundreds of thousands of dollars on her. I was going to make her a star.
And let me be even more frank, just to show you that I'm not a hard-hearted man, that it's not just dollars and sense: she was young, she was beautiful, she was innocent. She was the greatest piece of **expletive deleted*** I've ever had, and I've had them all over the world.
The along comes Johnny Fontaine with his olive oil voice and guinea charm, and she threw it all away. She threw it all away to make me look ridiculous! And a man in my position can't be made to look ridiculous! So you get the hell out of here! And you tell that goomba if he tries any rough stuff, I ain't no band leader. Yeah, I heard that story."
Hagan: "Mr. Woltz, thank you for dinner and a very pleasant evening. If your car could take me to the airport. Mr. Corleone is a man who wants to hear bad news immediately."
