Lucas screwed up the ending??? Please comment

Rating: Null/10 (19 May 2005)

First of all, Loved the movie. I think the best out of the 6. One problem, When Padme gives birth to the twins, the audience learns they are Luke and Leia. Now of course we all know this is not a big deal right because everyone in the world knows this. Well it is a big deal because without the prequels when we learn that Luke is Darth Vader's son and also that Leia is his sister it is the biggest shocker of movie history. Now if your from a different planet or watching the Star Wars Movies for the first time in order the whole shocking moment is gone because you know this already from Return of the Sith!
Not sure how he could have prevented this with virgin Star Wars watchers, I just think we shouldn't have been given the information of the twins in the end. Especially their names!!