My daughter went for the first time at 5 1/2, then went again last Dec. at a little older than 6.
The first trip - her favorite ride was Space Mountain - but her favorite park was Epcot. She absolutely loved the World Showcase (for the shopping!) and the Kidcot stations. We spent two full days there working on her mask, etc. She loved the Tapestry parade - we miss that tremendously!! She was going through a fearful stage at this point - wasn't fond of dark, scary rides or anything with FIRE! She hated Fantasmic!
In December, at 6, her favorite ride was now Rock N Roller Coaster (she is tall for her age!). She conquered her fear of fire and dark - and loved most of the other rides as well. She is iffy about Splash Mountain - she likes it okay, but doesn't care for the big drop (probably because we were stuck on this ride for 50 minutes on our first trip!) Spectromagic is a big hit, as well as Buzz Lightyear. She does not like the MGM park at all!! Even though RNRC is her favorite ride - she wants to go in - ride it - and get out!! This park makes her want to go back to the resort and swim! She loved AK and the Lion King show and the Safari. But again, Epcot was probably her favorite park overall. We did do the Princess breakfasts in both the castle and in Norway - we preferred the Norway one - food was better, IMO, and it was much more relaxing. We also had better character interaction - and we got JASMINE - our 6 year old's favorite!! We also had Mulan here - Snow White, Aurora, and Belle were at both breakfasts, while Mary Poppins and Cindy were only at the castle.
Don't give up on Epcot just because it's "educational". Future World has great interactive stuff along with the shows and rides, and World Showcase is just a blast!