Star Wars did have a larger impact, though whether that was a good or bad thing is debatable. It helped usher in the era of the summer blockbuster and tentpole film, which many critics feel sounded the death knell for the maverick period of the 70's.
And SW's achivements were mainly, as you say, technical. You can't really argue that Lucas' homage to serials of the 1930's added to the language of film, or that it was some kind of artistic milestone, whereas Annie Hall is a pretty distinct landmark in film comedy. You can see is in everything from Ferris Bueller's Day Off to Juno.
Also, in addition to being one of the funniest films ever made, Annie Hall is a great love story as well. What Keaton brings is not only her unique, kooky persona (which doesn't seem like a complete stretch from her real one, a la Ellen Page), but the suggestion of depth despite her naivety and occasional posturing that makes it believable someone could fall hard for her, and have trouble getting over her when it ended. Woody's notions about love, and the capstone of "we keep doing it because we need the eggs" isn't necessarily profound or any type of revelation, but speaks to the absurdity of the ongoing search for a mate in a way than anyone who's loved and lost should be able to relate to.
In short, it's not as slight as it may first appear.