I always thought the original Star Wars film was cartoon-like and it’s plot line aimed at a younger crowd (I was 15 in 1977). So I never caught the Star Wars bug. It was OK as far as special effects went, but the story was weak.
Lucas was trying to recreate the Buck Rogers / Flash Gordon type of story (the original, unused poster art concept even mentions those older characters) - so it makes sense that the story line is a bit thin - especially in the first movie. I think Episode V is the acknowledged "best" of the series because it has the most substance to it.