The only reason Empire wasn't received well was that it had a downer of an ending, and an unresolved one, whereas Star Wars ends jubilantly with the throne room celebration. Only in the context of all three films does Empire stand out as the best, since ROTJ, despite tying everything up, was too kiddie and felt kind of obligatory rather than sincere.
Into Darkness is a disposable blockbuster film that will be forgotten in 10 years.
I disagree with just about everything... Empire wasn't recieved well mainly because of its unconventional story structure: many reviewers felt it was just plain bad... And we'll see in 2023 who was right, you or me....