2 suggestions to recommend:
First: My youngest was 2 and a half when we first visited, he is 11 now. In one of the books I first looked at when planning a trip, a wise person offered the reminder that young children can go into sensory overload -- sometimes they need to take time out to play and they use play to process all of the experiences they have had -- the colours, the characters and the excitement.
I have found that giving the kids an hour or so in the room, playing with
lego, or cars, or soldiers, or anything they wanted, has been great. It refreshes them. So, sometimes, when the grown-ups really want to head out to a stimulating restaurant or can't understand why the kids don't want to dive into a noisy pool, remember that they need some processing time..and they might actually be happier on the balcony building a toy fort.
Second: On the boards we are all trying to make best use of the time we have, but sometimes you have to rip up the grown-up plans because the kids know best. We had one holiday in May/June where it was just too hot for us Europeans and the kids basically decided that they weren't park hopping until after 5pm when the sun was bearable. We didn't miss anything and we met a whole host of really nice people in the quiet pool at 1am who had also decided that sleeping in during the day and exploring Disney at night-time was the way to go.