Hello Jason!
This is such a great question. We visited Walt Disney World when our daughter was around the same age (she's been going every year since six months old) and you'll be surprised at just how much there is to do with the little ones!
For us,
Disney's Animal Kingdom Park (DAK) is one of our favorites to tour with small children. While there aren't a lot of attractions for small children, there is still so much for them to see and do. Our favorite attraction is The Boneyard. It's a closed-in area with lots of places to run, climb, dig, and explore. We spend at least an hour with our kids there every visit. (it's also a great place to wear them out right before nap time)
Kilimanjaro Safari is another great attraction for little ones. They love to check out all of the animals roaming the Savannah and get a thrill from speeding along in the Safari vehicle. Make sure to take time to explore the Pangani Forest Exploration Trail, located next to the Safari for some really fabulous animal spotting.
The Wildlife Express Train will take you to Conservation Station. Home to a petting zoo called the Affection Section, animal exhibits, and some special character meeting areas. You may run into Jimminy Cricket or Rafiki there!
And, speaking of characters, Camp Minnie-Mickey is our absolute favorite place to meet Mickey and the gang! (tip: head over while The Festival of The Lion King show is taking place for shorter lines). You can find lots of great characters everywhere in Animal Kingdom as well, many with shorter lines than you'd find in other parks.
I'm running short on space, but as you can see, we really love DAK for our small children. If you have any other questions, please come back and ask me!