Regarding Super 8, it doesn't really matter at all if the source material won't be remembered when building an attraction. If the attraction is made well enough, it will be remembered even more than its source material.
Waterworld is a good example of this. The movie flopped at the box office and no one really cares about it today, yet the show at USH still brings in crowds. Because the show was so popular, it was eventually cloned to USJ and more recently, USS. In addition, if USSK goes through, plans call for Waterworld to be cloned there as well.
I also brought this up in the Despicable Me thread, but another example is Mr. Toad's Wild Ride. The movie was not popular, even in the 50's. But Walt Disney knew that the idea of riding around recklessly, like Mr. Toad himself, was excellent for a theme park. Since it was built, it remains a Disneyland classic to this day.
Yet another example is Splash Mountain. Disney has refused to rerelease the movie Song of the South in the United States, but Splash Mountain remains a popular attraction regardless.
And there are tons of other examples out there as well.
(However, I personally wouldn't want a Super 8 ride to replace E.T.)