This a bad idea and to understand why you have to understand Roller Coaster Junkies!
I'm roller coaster JUNKIE!!! I'm about 5 -6 hours from Ceder Point and 2 hours from Six Flags Great Adventure NJ. I can't help but enjoy coasters.
Us Roller Coaster enthusiast are wired a bit different than the normal person. Roller Coaster enthusiast CRAVE coasters. But NOT JUST ONE. We want variety. We want to jump off one coaster and go right to the next heart-racer.
So for Disney, in order to please the group of people who would really appreciate a true trill coaster, Disney would have to build MULTIPLE coasters. Essentially, the WDW parks would start to resemble IOA. I love Disney for what it is (although as of late they've been dropping the ball) which is a great place for families. No Coaster Junkie would go to Disney for ONE coaster. Disney would just waste space trying to please the hardcore people like me.
I actually think EE, SM, and RcR are perfect coasters for Disney. I want to be able to take my son on his first Coaster and Disney offers the perfect types of coaster for that occasion.
Besides... could you image THIS thing in a disney park?
http://youtu.be/1iD6gxLEbNU