MK needs a variety of rides, which it always has since it opened, in order to stay competitive. When the competition adds more thrilling rides, so should Disney, but only the way Disney does it. If they don't, more visitors will skip Disney in favor of Busch Gardens or IoA.
MK a supposed to have multiple mountain ranges, preferably one in each land. Adventureland is the most lacking of all the lands and needs something big in order to balance out the rest of the MK. DL's Adventureland has Indiana Jones (great ride, by the way), balancing out the MK there. I would like them to build Indy one day at DHS (as well as the Indy roller coaster from Paris), next to the stunt show, to make an Indiana Jones mini-land.
The volcano alone of Fire Mountain would have been seen across the Seven Seas Lagoon at the Polynesian, adding to the theme of that resort. At night, the erupting volcano would have glowed brightly on the lagoon, adding an amazing visual experience for the riders, as well as resort guests. The pyro techno effects on the ride would have been amazing. At the same time, it's a perfect Disneyesque response to similar ride technology at competitors' parks.
It also would have started a themed pattern WDW mountain ranges of elements: fire, water (Splash Mountain), and ice (EE).