We had people tell us AK was "a glorified zoo". Well, we were going for 5 days and wanted lots of MK time, so we did 3 days at MK, 1 day at EP and 1 day at HS. The next time we went, we decided to try AK. We went from open - parade (about 4pm). We left knowing we would come back for another day, but we only saw about 1/2 the park. We loved it. We saw and took time to see the animals, met characters, saw FOTLK, did the Safari, It's Tough to be a Bug, had a caricature made, did some of the games and activities along the routes, saw some streetmosphere, traded pins, and had lunch. We stayed for the parade, but it got rained out. We were there 7 hours and still didn't do anything in Dinoland, Asia, or Rafiki's Planet Watch. And Dino and Rafiki are definitely kids areas. So, yes, I think AK has plenty to do for both kids and adults. We all loved it and plan to spend 2 days there this upcoming trip. Disappointed that the parade will be gone, because I never got to see it. And now that there is the Wilderness Explorers to do, I'm sure we will easily fill our time.
I still can't figure out why others find this a half day park. However, I suppose once you've been there, you can narrow down what you like and skip the rest. But if you haven't been, I would think you could find plenty to do. Do your research and find out when there are street performances. See Divine and the music in Africa.