Episode 4 Mediocre? The movie that launched it all? The movie without which we wouldn't have most of the sci-fi that followed it? The movie that started the special effects revolution? It was lightning in a bottle. It was a once in a lifetime alignment of the stars to create an event. Star Wars was not just a movie, it was an event. The first big major out of nowhere blockbuster hit that all other movies strive to be. Every movie that has come since begs to be the phenomenon that Star Wars was.
Mediocre you say? BULLS**T says I.