As a rule? It’s hard to call Jaws, Close Encounters, E.T. and Schindler’s List ‘bad scripts’. But in this case the script is irrelevant. Hitchcock’s ‘Vertigo’ has a script that’s completely implausible - it doesn’t matter.
The early days he did well, Jaws is one of my all time favorite movies. Since the mid-80s it’s a different story. Script matters, Vertigo is one of my least favorite Hitchcock movies, it’s just all around annoying.