I don't really agree with the idea that Animal Kingdom is one to be finished quickly. I, personally, find a day at AK to be too short, because of the great rides that are there. Sure, you've got time to ride everything once (if it isn't too crowded or you get decent FastPasses) in a day, but with a great coaster like Expedition Everest and a great water ride like Kali River Rapids, multiple rides are a must, at least, for me and my sisters and brother in law. Plus, there's the Primeval Whirl in the Dinosaur section, which is the first and only wild mouse style rollercoaster I've ever ridden, and Dinosaur, which my mom loves to ride at least a couple of times. There are several good shows, too. I highly recommend "Flights of Wonder," and I've heard that the Lion King show is a must, though I've not actually seen it yet myself (I'm actually not a big show person). "It's Tough to Be a Bug" is a fun show, too, but it might not be ideal for really little ones.
My family tends to go in late summer, early fall, and I'm not sure if this holds true for more crowded parts of the year, but every time we go we ride Kali River Rapids just before closing time, and are permitted to stay in our boats for multiple rounds on the ride because there is no one in line. I'm fairly sure that those nights were on Extra Magic Hours. And getting wet at the end of the night works out really well, I think. I inherited the concept from my mother that it's best to save the water rides for the end of the day so that you don't have to walk around the park all wet. Plus, water rides typically have shorter queues at night, because the crowds ride in the heat of the day to get cooled off. As far as being cold after you get soaked at night, it'll happen. On Kali, though, when you're riding multiple times, you'll learn to appreciate the burning forest section of the ride for the heat generated by the fire. I don't think I've ridden it during the day, but I'd think that the fire under the Florida sun is a bit overbearing.
I guess I got off-topic with my second paragraph, but my point is that, if you like the more thrilling rides, and you're the kind of person who wants to ride the best rides multiple times, you might consider multiple visits to AK, or at least a visit on a night with Extra Magic Hours.
Oh, and I'm thinking the problem that most people have with AK is the traffic flow. It's not great. And it is worsened by how hot that park seems to get. Oddly, I kind of appreciate how hot it is in AK. Since the park is themed after tropical locales, I feel like it adds to the realism and ambiance. And, as far as ambiance, I think Animal Kingdom does an amazing job of convincing you that you're in Africa, or Southern Asia, or what have you. That is actually my favorite thing about the park.