You have the Sidious/Palpatine identity, and we can debate whether it is effective or not, but it is made for the 1-6 viewer. Then you have the last 15 minutes of ROTS, once Anakin gets slashed by Obiwan which is clearly made for the 4-6,1-3 viewer, as even Lucas states it in the ROTS commentary, "There is alot of these scenes I didnt' need to put in here at the end, but I knew that the older SW fans wanted to see this stuff, but I didn't need to put it in.
Another example is you have QuiGon use the jedimind trick in the first 10 minutes to Boss Nass, which would go right over the head of a 1-6, cause Alec Guiness doesn't explain it til the beginning of Episode IV to Luke. You have Yoda just appear in Episode I as the council head, but to a new viewer, what does that mean, as to his first appearance in Episode V, where he totally plays Luke and the audience as THE Jedi master. Another example of screwed viewing is Yoda dropping his cane in Episode III when Order 66 happens, but again that isn't explained til Episode IV when Guinness talks to Luke about HOW he feels when Alderran is blown up. So what has happened is you have all these introductions to plot points in the back half of the story now! Let me know how many movies, books, TV shows you have ever seen where everything is explained or recapped halfway through the story!