Wow it's been awhile, but never fear! WDW is still as awesome as ever!
Out of all the four theme parks, Magic Kingdom definitely changed the most.
There's the All-New Fantasyland Expansion, which is spectacular!
The expansion includes two new rides: Under The Sea Journey of the Little Mermaid, and Seven Dwarfs Mine Train. Both are great fun!
New Fantasyland also includes sub-land called Storybook Circus, which is basically a re-themed Mickey's Toontown Fair. Storybook Circus also includes the new dueling Dumbos with an all new playground queue! It's pretty neat, especially for the kids.
There's also Enchanted Tales with Belle, which is a different and more immersive meet and greet, Princess Fairytale Hall, and the Be Our Guest Restaurant, which is a huge MUST!
Here's a list of other new"ish" experiences:
* Obama in The Hall of Presidents
* Big Thunder Mountain queue changes
* Pirates of the Caribbean featuring Capt. Jack Sparrow, and Mermaids.
* The original Tiki Room Show minus Iago and Zazu.
* Sorcerer's of the Magic Kingdom (interactive scavenger hunt)
* Pirates scavenger hunt in Adventureland .
* Interactive queue in Space Mountain, also featuring onboard soundtrack and improved effects.
* Monster's Inc. Laugh Floor
* Talking Mickey in Main Street Town Square
* Festival of Fantasy Parade
* Return of the Main Street Electrical Parade
..And more!
Epcot:
* Re-imagined Spaceship Earth, featuring an all new narration and interactive features.
* Sum of All Thrills at Innoventions. (You can create your own roller coaster and ride it!)
* Re-imagined Test Track, featuring all new effects and storyline. You can now customize and create your own Chevy car and compete against each other.
* Return of Captain EO at Imagination!
And more!!
Disney's Hollywood Studios
* Toy Story Mania, a interactive shooting gallery ride similar to Buzz Lightyear's Space Ranger's Spin. Very very popular!
* Capt. Jack Sparrow Interactive Walk-Through, not sure of the exact name..
* Disney Jr. Live, similar to Playhouse Disney Live.
* Star Tours: The Adventure Continues, a re-imagined 3D version of the classic attraction, featuring all-new effects.
And more!
Disney's Animal Kingdom:
* Relocated Festival of the Lion King
There's also a whole expansion and refurbishment going on at Downtown Disney.
They also added a few more hotels: Art of Animation, Bay Lake Tower at Disney's Contemporary Resort, and more!
You should definitely make plans to go back!