Hi Jagena:
I've heard it before. Epcot has "that" reputation it just can’t seem to shake. However, I have two boys, eight and six, and aside from Magic Kingdom, their favorite Park to visit is Epcot.
At Epcot, we take in Soarin’, the newly refurbished Test Track, Spaceship Earth, Mission: Space, Living with the Land, the Innoventions pavilions, and visit The Seas. We also tour the countries of World Showcase. A high highlight of World Showcase for my boys is Agent P’s World Showcase Adventure, an interactive experience around the pavilions. They also enjoy learning about different cultures as they interact with Cast Members from around the world.
I would look at those specific attractions online with your kids and see if they get more interested. However, if your family ultimately is not that excited about Epcot, I would not push it on them. You may want to play it by ear. While my family would have no problem with three days at Magic Kingdom, given the variety of rides and attractions, if your family feels they have “done” Magic Kingdom by the end of the second day, maybe you will all be inspired to give Epcot a try on that last day.
Enjoy your vacation.