I've been this time of year several times, and I would have to agree with moderate crowds. The afternoons are going to seem quite busy and I would expect there to be fairly large crowds for Fantasmic, Illuminations and Spectromagic. You'll want to be sure to arrive early for the nighttime activities.
A good plan would be to arrive early to the parks, get as much done as you possibly can, spend some time back at the resort during the busy afternoons, and then return to the parks in the evenings for the parades and fireworks.
Have fun!