Definitely would have kept the Genco scene in the movie. It explains and establishes a lot.

I also like the script's version of having Michael personally kill Fabrizio. It fit with both his personaltiy and that of his father. Notice how Vito had to personally kill the old Don and in the deleted scenes his two henchman by annoucing who he was first. He wanted them to know who it was. When it came to a personal killing, he was confrontational.