All very well, Ming, but if you check the facts it doesn't actually pan out that way. Lucas' divorce was in 1983, around the same time as Return of the Jedi came out, and it was ROTJ that suffered because of his personal issues and lack of caring (and firing of Gary Kurtz, who was among other things of the kill-off-Han camp along with Lawrence Kasdan, who still co-wrote the thing, and Harrison Ford). I never got the impression that he didn't like the sense of plotting and pacing and character development we got in ESB: if he didn't want a softer, darker, more character-driven film than Star Wars, he wouldn't have hired Irvin Kershner to direct it! He certainly appreciates ESB and has said that the structure of ROTS on some levels deliberately mirrors it: start with a big battle and escape, characters split up, have character moments, lightsabre duel at the climax and the good guys get away by the skin of their teeth and vow to regroup at the finalé.