As great as a job Kersh did with ESB, I am always weary when a fan says that the next sequel of that series he directed would be a slam dunk.

Jurassic Park is a classic directed by Spielberg, but Jurassic Park II is a horrible movie (IMO) also directed by Spielberg.

Lethal Weapon series gets ALOT worse with Richard Donnor directing all 4 movies. The original is great, part II is a very good sequel, but part 3 is OK, and part 4 is really awful.

Many fans say Jedi (or the PT) would have been better if Kersh directed, but you just don't know. Classic movies in Hollywood are very rare, so the easy bet is that they probably can't duplicate the greatness of the previous movie.