I don't know if that's particularly true to be honest. They could all be good films and you'd still have to show that Sidious is Palpatine, that Anakin is Vader, and that Luke and Leia are siblings. I've heard it said on here in several of the 'explain your viewing order' threads that when you choose which trilogy to start with, you pick which dramatic reveals you want to keep and which you want to spoil, which is true. So you've got to pick between I am your father, Luke and Leia are siblings and Vaders turn at the end against Anakin's fall to the dark side and the Chancellor being outed as a Sith Lord as your big twists. (Arguably the Machete Viewing Order preserves all of these in their own way but whenever you recommend that you get people coming out of the woodwork shouting TAHTS NOT HOW LUCAS WANTS YOU TO WATCH IT. As far as I'm concerned if Lucas wants to lock in the order I watch the films in he can also bring the popcorn and drinks when I watch them, otherwise I'll make my own mind up).