The first thing we need to consider is that we're dealing with THEME PARK ORIGINALS, and for that, they should be respected. All changes should be made in accordance with the spirit of the original attraction - not movies, tie-ins, etc.
In order of least-to-most:
5.
Space Mountain - The ride is still popular, there will be a version closed at Disneyland for an entire more year, and because it still thrives off of thrill, other attractions should be given rehabs first.
Changes to be made - New track? Musical score? I'm not too sure, I'm not really digging the musical score, as the WDW version's darkness/screaming adds a little to the nostalgia factor. I would bring back the theme song and bring in an awesome new post-show. I am somewhat more impartial to this attraction. Whatever they do, just keep the building white.
4.
Pirates of the Caribbean - Honesly, I don't think this attraction needs a rehab as much as others. Show quality is excellent and can only be
improved upon. Whatever is done -- no movie tie ins! Leave that for the theatre or DCA/Disney-MGM.
Changes to be made - New animatronics? Better speakers? More effects? Certainly! But be sure to keep the cooky pirates, and the overall atmosphere. Much can help.
3.
Country Bear Jamboree - The original "Magic Kingdom classic," CBJ still draws in the crowds, and therefore a gut would be unfair. Disney should also know by now that "Under New Management" shows just
doesn't work. But this attraction needs improvements.
Changes to be made - New sound system, first and foremost! That's the big one. The animatronics are in good condition, now that they are under a new digital system, but new animatronics with the latest features (will Disney INVEST in this?? I would flip in joy if they did), but, of course the same show, same characters, same spirit.
2.
Haunted Mansion - No doubt this one needs it the most. The doombuggies sway from side to side after changing position and the sound system is horrible (especially in the doombuggies themselves). But the attraction remains one of the most definite Disney classics.
Changes to be made - New soundtrack system, maybe get rid of those popping ghosts - maybe
, brand new track installed, whatever. Bring in the latest special effects, but keep the eerines (perhaps its sign of age MAKES it eerie today?? Perhaps).
But the biggest attraction that needs rehab the MOST - in my opinion - is no doubt
1.
Walt Disney's Carousel of Progress - Walt wanted this one ride (dedicated to him, if he knew it or not - at least his vision) to be open as long as the parks existed. Successful seasonal (and even an upcoming year-round) operation and polling that guests love "progress," too. However, it won't have the same lines as Space Mountain - or perhaps even Country Bear Jamboree - because its hidden in Tomorrowland and isn't even advertised properly in the Tomorrowland Transity Authority.
Changes to be made - First -- NEW ANIMATRONICS! Second - reglorify the pavilion. Make a new outside sign have motion and banners (ala World Fair?) and retheme the pavilion to a more pleasing, more state-of-the-art design. Next is the theatre - glorify them. Make the sound system OUTSTANDING (especially the theme song tracks, which are in need of volume and more instruments). New script, new final scene, but one thing should remain consistent - and that's progress.
So far, the only attraction on this list that is planned to go down for rehab is PIRATES OF THE CARIBBEAN. This would happen later next year.
The HAUNTED MANSION was originally slated to have a rehab this past winter, after a Haunted Mansion Holiday premiered. It was cancelled.
Are you denying the love for the expression on this thread and to the attraction itself? 
