We went last year for the last weekend of Star Wars (June 12,13). Our 9 year old was in heaven! I think it was worth it. The crowds weren't bad. It wasn't like you couldn't move. We never waited more than 10 minutes for an autograph/photo, and we saw Chewie, Darth Vader, C3PO, Princess Laia, Darth Maul and many characters I didn't recognize, but my son knew. Plus the stormtroopers were always marching around and so was the Emperor. And they all stayed in character. No fastpasses required. That being said, we didn't arrive in time to see the "special guests" for that weekend. Every weekend they have 3 actors who played in the films. The weekend we were there it was the boy who played the young Boba Fett and 2 other guys. You could get a type of fastpass to meet and greet the actors, but my son wasn't even that interested in seeing the actors there that weekend, so we didn't bother. Now, if they had Jango Fett or the adult Boba, he would have loved that.
Ds did the Jedi Training. I think they had it every hour. They select kids from the audience to participate and they pick ALOT of them...at least 20. Our son wasn't picked for the first show, so we didn't stick around to see the show. We came back for the next show and he was picked! There weren't that many people at the show, so I think if you're willing to go to 2 or 3 of them, your son will get picked. It was quite cool.
I'd highly reccommend the SW weekends!