Whether anyone agrees or not, eventually all film systems at Disney will be pure digital. That's simple fact for modern media solutions, lower long-term operating costs, and better attraction experience. When...we don't know. With what incarnation of projection technology...we don't know. But we can be assured it will happen.
I agree with other posters that a simple IMAX swap to existing systems is out. If anything happens, it will be a major moment for all of us here.
Now as for 3D...we all know that it's use in theme parks for 4D experiences such as The Muppets or Philharmagic is classic and intentionally gimmicky for the fun and surprise factor. Soarin' is going for realism. Right now it does a good job of pulling us into the ride and making it a real thrill, based solely on screen size and curvature. I'll venture to say (knowing that anything is possible), that I seriously doubt we'd ever see Soarin's current "Over California" movie in 3D. However, it would not surprise me that if a new movie is/will be filmed, it will be filmed in digital 3D. That way they could present it in 2D using only 1 of the 2 views, with film through simple prints from the digital, or upgrade the projection system and go full digital 3D. Only makes business sense.
I know this isn't news and all of us that frequent the forums know this. But it seems reasonable to state so we can search the site in 3 years, pull up this thread, and say "Oh yeah, there it is. See, we predicted that." :wave: