It sure isnt a museum. So when and if they gut SM, they oughtta go ahead and redo Pirates.
I think you need to stay true to Walt's vision, which was to have a place where the entire family could have fun together. That means a blend of rides, something to appeal to Grandma, something for mom & dad, Dumbo for the kids, and a few thrill rides for the teenagers/young adults.
Pirates is an experience that can be enjoyed by the entire family. It's an immersive ride. The rider is meant to feel like he is actually riding through a coastal town being overrun by pirates. As such, it doesn't matter so much if the technology gets old as long as the effect still works. That said, new technology that can enhance the experience is (and should be) welcomed and added to the attraction. Over the years it has become a Disney classic, a Walt original, and it is understandably beloved, and people don't want to see it change. And all of that is ok because the original immersive goal of the ride is still accomplished. It still works, it still accomplishes its original goal.
Space Mountain is a completely different story. It is a THRILL ride. Perhaps the ultimate thrill ride. When SM opened it was considered one of the scariest attractions on the planet. I can remember people talking about it with great FEAR, rumors circulating about people who freaked out or passed out in line and had to be evacuated. If you were brave enough to go on Space Mountain, you had real courage.
Space Mountain no longer serves up the same level of thrills. Now it's a "cute" coaster. People ride it with nostalgia and remember the first time they rode it. There is no fear and very little excitement. Unlike Pirates, it no longer accomplishes its original goal of providing a true thrill ride inside the Magic Kingdom.
This is an important point when you consider what Disney's competition is doing - bigger, faster, more extreme thrill rides. The best way for Disney to respond to this is with Walt's original vision - a blend of attractions to appeal to everyone in the family. Disney's thrill rides should be of higher quality, better themed, technologically advanced, and lots of fun. (Everest fits the bill nicely.) Space Mountain is really none of these things anymore (the theming is still ok but really starting to look dated, like how you can barely see through the "control room" glass because it's so dusty and faded.)
The bottom line is, we need a new Space Mountain. One that can serve up all the excitement and thrills that the original did in the 70s.