It's been 2 years since I last did WDW. I'd try to hit 2 parks at least if you have multipasses.
EPCOT has undergone some changes: World of Motion is totally redone, I miss some of the old one, but the new one is a blast, and about as "rollercoaster" as it gets (That's not saying much, it's honestly nothing major, but it's alot of fun without the bumps, hills, loops, etc of a coaster).
Communicor is gone, replaced by something else with sorta the same idea. Energy rocks... Body has a motion simulator which might make some people ill... it's kinda jerky. When I was last there, Horizons wasn't open at all, so no clue what's going on there.
The Ball is nice and slow; might freak out people in the end, but nothing has really changed... Same with the living seas and the land (although, supposedly the land has some new movies and shows, etc).
Last I knew, the "world" had hardly changed, still a boat ride in mexico (always get the chirros) and norway, the 360's in China (never liked that one) and Canada... and the American showcase thingie. There was also a kinda tent place where they had "minor" countries that they were planning to rotate members every couple of years.
The other non-coaster kinda place is Animal Kingdom, which has a ton of shows, safari rides, a thunder river, log flume, more shows, etc, and is really a cool place... if you go there, GO EARLY and hit the Safari, then figure out the shows to do (Tarzan Rocks is pretty sweet) and place your other rides between shows.
Anyway, have fun