Disneyland was only open for 11 years when Walt died in 1966, and yet Pirates of the Caribbean wasn't even open until 4 months after he passed... However, a quick search for the Disneyland rides that closed before his death in December of 1966 include: the Main Street Shooting Gallery, Stage Coach ride, Mickey Mouse Club Circus, Flying Saucers, Phantom Boats, the original Astro-Jets (ground-level), 20,000 Leagues Under the Sea walk-through exhibit, Monsanto House of the Future, the Monsanto Hall of Chemistry, and the Viewliner Train of Tomorrow. All of those officially closed in that 11 years, and other attractions (or features) were built in their place. Some weren't torn down, but upgraded or expanded in that time, like Rainbow Caverns Mine Train (expanded, and then finally closed in 1977) and Rocket to the Moon (closed in 1966 and became Flight to the Moon in 1967)
You may not consider any of these attractions to be particularly notable, but I'm sure that some people had fond memories of some of these early attractions... I do enjoy watching historical videos about these lost attractions, as well as Walt's one NY World's Fair attraction that did not make it to Disneyland: that being Ford's Magic Skyway. (featuring the dinosaurs from the DL train tunnel diorama) It's noteworthy that It's a Small World, Carousel of Progress (later moved to MK), and Great Moments With Mr Lincoln all came over from that same world's fair, and are actually 2 years older than Disneyland, itself.
I'm Walt's own words:
"The park means a lot to me in that it's something that will never be finished. Something that I can keep developing, keep plussing and adding to—it's alive. It will be a live, breathing thing that will need changes.
"I wanted something live, something that could grow, something I could keep plussing with ideas, you see? The park is that. Not only can I add things but even the trees will keep growing; the thing will get more beautiful every year. And as I find what the public likes—and when a picture's finished and I put it out—I find out what they like, or they don't like, and I have to apply that to some other thing; I can't change that picture, so that's why I wanted that park."