The only thing that would have made the ending better...
If, during that final rendition of "Twist and Shout" in the Cavern, we'd seen a slender, well-dressed young man in the crowd, not dancing along with the others, keeping a steady, thoughtful eye on the group onstage...
...leaving us all, at the tail end, right on the cusp of history being made!
ETA: Actually, my history's a little rusty--did they learn of Stu's death *after* Brian had signed them on? Oh, well, even so...it wouldn't have been the first time a movie had taken historical license for the sake of a good scene.