Tomorrowland 1967 and the original Epcot Center had they been left alone would still be relevant today with just minor tweaks here and there (updated last segment of Carousel of Progress, Standard Pavillion refreshes, etc.). Stuff like Innoventions and Mission Space was dated the day they opened.
Mission Space had huge buzz when it first opened, and was not dated. The continuing problem is that (1) You don't feel the need to ride it more than once: and (2) People died on it. My son who was about 7 when the green version opened, and loved it. We rode it multiple times, but only rarely ride the orange version. Now we maybe ride it once per trip.
People don't want to risk sickness on vacation, which was the 1st problem with it. The second problem was that people died. The third is that it's pretty cool the first time through, but the novelty quickly dies off once you know the whole scenario. What they need is different scenarios ala Star Tours. We now ride Star Tours over and over because you never know which version you're going to get. If Mission Space ended up in Mars or Jupiter or Saturn, it would be fun to ride it over and over. Instead, it's just the exact same trip to Mars every time.
I didn't get to Epcot in the 80's, but from what people tell me, Innoventions was pretty cool in its day. It was apparently like a Science Museum of today, with lots of hands-on stuff. This was back in the day when Museums were places to just walk around and look at stuff, not somewhere that allowed you to explore places, press buttons and pull levers. Innoventions allowed visitors to do much more than that, which was actually a cutting edge concept that forced other such places to catch up. Now, every successful museum geared toward families has plenty of places for kids to do hands-on things.
I also think Tomorrowland needed more than tweaks. Remember, Space Mountain didn't exist on opening day. Their biggest mistake was Stitch, and their drive to mediocrity is best illustrated by the wimpy, commercialized, vanilla, pointless, obtuse, unimaginative and just plain bland narration of the People Mover. It used to be a clever and fun narration with a strong-voiced commander contrasted against a smooth female voice announcing things about Tom Morrow and giving your party from Saturn a ring. Fun. Now it's Mr. WimpyVoice saying everything is "Out of this World". Writing the new narration probably took a good 10 minutes in a beige windowless room. Instead of an Imagineer, they used a Blandineer.
Again, safe decisions that Walt never would have made.
