Space Mountain (although it will be different than what we have now)
Buzz Lightyear will be replaced
Astro Orbiter will still be around (tough to replace and it's the "focal point" of tomorrowland)
CoP will be replaced
Stitch's Great Escape will be around...but probably ready for replacement.
Timekeeper...heck, it's pretty much gone already.
TTA will be around
Pooh will be around
Snow White will be changed but remain Snow White
Peter Pan will be refurbished
IASW will remain.
Tea Cups will remain
Dumbo will remain
Caroussel will remain
Haunted Mansion will remain (although refurbished)
Riverboat will remain
Hall of Presidents will remain
TSI will remain although it may be changed with more "updated" materials and "attractions"
BTMRR will remain
Splash will remain
Pirates will be refurbished but always be Pirates
Jungle Cruise...tough one.
Tiki Room...tough one.
Aladdin will remain
SSE will still be a big ball

UoE is tough
Test Track will be updated or added to.
Mission:Space will be added to and a new film will be there...heck, maybe on M:S 3 or 4 by then LOL
Imagination...who knows.
Land...already getting additions...Soarin' will remain but most likely have a new movie.
Muppets will get a new flick.
Star Tours will get a new flick.
ToT XX.
Rock N Rollercoaster will get updated track listings
HA HA HA...who am I kidding!!!
20 years for all of this??? I think it'll need to be a LOT more time before ALL this gets done!