I would say if you don't have kids OR generally aren't into the Disney animated movies, skip MK. Even when DH and I do MK these days, it's basically Thunder Mtn, Haunted Mansion, Tiki Room, Carousel of Progress, PeopleMover, and Little Mermaid (when the line is short, which is often).
We'd rather spend the day at AK when we can stroll around the park and do all the animal walking attractions. It's true there are less rides than some other parks. But there's great entertainment, some amazing food and drink options, and beautiful atmosphere. Just remember to wear a hat if you go into the bird room! The downside of AK is that it can be hard to find a shady place to sit and relax.
I honestly feel even EPCOT has less attractions than Animal Kingdom but again it's personal. I think we really only care about Spaceship Earth and the new Remy ride. The headliner rides "Soarin, Test Track, and Frozen) are not bad, but just not worth the wait IMO. I'd rather breeze through a line for Living with the Land or Grand Fiesta Tour.
Hollywood Studios is a bit of a toss up. If you're a Star Wars fan it's a must. It has a bunch of great rides but all of them have loooong lines. Unlike MK/EPCOT, HS is compact so the "shorter line" attractions aren't pulling enough people away from the big ticket attractions. Also, due to lack of foresight by Disney, it doesn't have a unified theme which means the overall atmosphere suffers.
Again, these are all just personal opinions

as you can see people have pretty different opinions about each park.