My son LOVED the Passports & Kidcot stations when he was younger (he's 16 now)
When he was 10, I couldn't keep him OUT of the World Showcase - We spent from open to close, getting stamps, doing Masks, talking to CM's. I loved it, I've always been into World Cultures. I was surprised that DS was so into it, as that was never a big thing for him.
I can't recommend it enough. We are taking my Grandsons in Dec & even tho they are only 3 & 5, we will probably get them a Passport. They will like the stickers & getting the stamps. It's never too early to introduce them to other cultures. They will definately Love the Kidcot stops.
Epcot has always been our Favorite. When DS was younger, it was tied with MK.