Yeah, in a way. It ruined it because Lucas didn't have either the talent or sensibility to go that direction again. He could have, though--ESB could have been the film that took a fun homage to adventure nostalgia and re-directed it into one of the most interesting and touching fantasy dramas in modern movie history. But it wasn't, alas. It did make Lucas take the future films in more heavy-handed "Serious" directions, though, but he couldn't let go of the kiddie-pandering aspect and he didn't know how to make the drama really work. That why, for every film after ESB, you have stupid, child-pandering elements, half-executed "mature" elements that don't mesh well with the aforementioned stuff, and one or two real, honest well-crafted moments of human drama.