I would schedule 2 days for Epcot. There is just so much to see and do. Since you have small children, don't forget to do the Kidcot stops. The last time we were there, they passed out masks that the kids got to decorate in each country. My kids loved it. Some countries even have something extra at the stops. In Japan they made the kids little origami animals. Most of the countries have little shows. Check your guide map for the times. My son was thrilled with the Japanese drummers. The acrobats in China were a huge hit, as were the living statues in France.
Also, if you want to check out the WS cuisine, I would recommend the following for small children:
Morrocco: They let the kids dance with the belly dancer. My daughter, who is usually shy in public, went right out and danced in front of everyone. The food is good too. Shish kabob type things and rice.
Japan: They put on quite a show when they cook your meal at your table.
Germany: The Biergarten restaurant has fun musicians--a rollicking good time.
Mexico: If your kids aren't afraid of the dark or the volcano, it's very nice.
(France and Italy are good, but seem to be better suited for a nice romantic adult meal.)
Future World has a ton of stuff to do. Don't forget to check out Imagination and the pavilion that deals with the body (what is it called? temprorary brain freeze--sorry). They have a lot of hands-on activities for the children. We practically have to drag our kids out.
Also, they have water fountains that the kids love to play in. The next time we go I will finally remember to pack their swimming suits when we go to the park.
