Until they added Pandora it was the lowest park on my list, so I didn't go there much prior to that, so I have a bit of a list. lol
1) The temp. It always feels like the hottest park in the summer because of the humidity. It's the one park I'll abandon if it gets too hot.
2) There is no easy visual way to get one's bearings just by "looking up" or at the horizon. In all the other parks you can easily see and sense where you are, with AK you can't. That is not a bad thing, and promotes exploring, unless the heat is getting to you and you are trying to escape quickly (see point 1).
3) For some reason I can't explain I don't like the view you get looking "down" on the Tree. You see too much pavement when you first enter juxtaposed with the tree as a backdrop. (MK: other buildings down a paved street with a castle. EPCOT: Metal and monorail and pavement, other structures, the ball. DHS: buildings, pavement, more buildings, theater.) Notice how there's not a big disparity between the entrance materials and theme vs. the icon you are supposed to focus on. This one is probably all just me, but the view isn't breathtaking to me like they want it to be. Now, the rest of the park, and the views when you get "inside" and up close to the tree and further into the park proper are fine.
4) They've actually fixed a lot on my list over the years so I won't go into those former gripes. I have to give them credit, and now AK is a must-do park for me.