Here's why I would skip AK (my opinion):
I'm into bang for your buck and although I really like AK, there are only a few activities my kids (2 & 5) experience. They go on the safari ride (my DS fell asleep on it two different visits), play in the boneyard, visit the characters (only did that once), and go on the dinosaur twirl ride (like dumbo).
Some of the other attractions are too scary (bug's life), or they are too small to go on the attractions. We have walked the trails (nice way to see the animals), but I don't remember them ever talking about it after the fact.
I find that with only a couple attractions they like to visit, there is a lot of walking! Lots and lots of walking!
Not a lot at MGM either, but the park is more condensed.
The whole family loves EPCOT. Don't miss the lady at the Japanese pavillion who makes the candy animals. She has been there at least 5 years if not more. She always has a huge crowd watching her. The kids liked doing the masks too.
Good luck on your descision.