I would skpi AK in a heartbeat, we spent half a day there in 2 weeks...I really don't like it. After making 5 trips in 18 months, you can only walk the jungle trails so many times. but this being said, I'm not a fan of animals at all.
MK is just SOOO much more crowded than the other parks, it annoys me SOOO bad!
MGM I love! I could just walk around there and be happy!

I love RnR,TZToT and GMR and Muppets!
Epcot is my favorite park and we spend most of our time there, we go once a day! it helps that we just walk over from BCV or BWV...lol. WS is amazing, I didn't realize how much there is to do there!
I would say, if you want to do AK, do a half day(you can get pretty much everything done), and switch over to another park. Definately tkae advantage of the park hoppers!