What are your kids into? Mine are a teeny bit older now, 13 and 15 but love all the parks. They do prefer parks with more thrill coasters but they do enjoy visiting the disney parks as a family but as they've gotten older, we'll probably plan some Universal time so they can get some thrill rides in.
They enjoy when we do the festivals at Epcot and sampling different foods. They do enjoy world showcase more as they've gotten older. They're favorite rides can be found in all parks and I'd say they enjoy WDW for a lot of the same reasons I do, it's a unique experience that you can't get at other theme parks.