Space Mountain and RnRC are extremely amazing rides for thrill seekers. I wouldn't say either of them are dated outside of Space Mountain's ride mechanics. It's a Small World is, again, a great ride for its intended demographic. My dad was pointing out during our last trip while we were riding it, how the design of the ride keeps little toddlers engaged the whole time. And sure enough, the 4 toddlers on the boat ride were mesmerized by everything around them the whole ride.
Speedway and Peter Pan have terrible capacity problems. And Buzz is still terribly relevant today with the popularity of Toy Story.
I can get behind updating the ride mechanics and some new show scenes for Buzz... But if it were to stay as is, I personally believe it would be fine. Because again, I've always enjoyed it, all my first time friends enjoy it, and I just don't feel a "datedness" to the ride. It's a video game. It's fun.
Any other examples?