Wow - lots of people thinking just of their own family. "Ride x we hate, ride z is boring for my kids, ride q my spouse and I avoid..." At the risk of getting flamed, Disney is not just for one family. Just because YOU don't like a certain ride doesn't mean others don't. Yes, I realize in my Disney fanaticism I am defensive of rides that are staples to the parks - Spaceship Earth, Splash Mountain, Star Tours, Jungle Cruise, etc. I As a side note, I think the appeal of JC is the tour guide - they are very talented people who remind me of the street performers in MGM. The ride is secondary to them, but yes, they could certainly update it. I'd just hate to see it go.
There are some rides that are "misses" as far as popularity goes, but as one person said, there are LOTS of people who have yet to experience Disney magic, and to tear down something as recognizable to people everywhere as the "giant golfball thing" (Spaceship Earth) is probably not a good move. Update it - I'd certainly love it if it didn't stop so often, and I recognize that Jungle Cruise isn't as "real" as Kilimanjaro Safaris, but it seems to me that the whole place isn't meant to be REAL. If that's the case, why would we all run toward people dressed in animal suits? There's an element of fantasy and magic that's supposed to be there. Disney's magic isn't that the rides are the most up-to-date or feature the most amazing effects. Some of my favorite rides are my favorites because they remind me of past trips, my favorite Disney movies, etc. You can go to your local amusement park for thrills. Disney is special to me because of the atmosphere, and some of the rides that people seem to want to get rid of are what I think of when I think of Disney.
That being said, this is a very interesting thread because I always assumed that people all love most of the rides (based on wait times), so I'm really intrigued by who likes/dislikes what and why. I DO NOT mean to sound "holier than thou"; I just am genuinely surprised at how quickly some people want to raze the classics. I'm just glad that we aren't the ones in charge of the parks because I think there'd be changes every day and the magic of WDW would be very different than what it is.