For a great in-the-park option, I highly recommend Tusker House at AK. It’s a character meal, also, but totally fine for just adults to do. A pre-rope drop reservation would be great here!
The Wave at the Contemporary resort is, in my opinion, underrated. We had an excellent meal there, and I think it’s a one credit. We did dinner, but I have heard great things about their breakfast buffet as well.
I think that Le Cellier is overrated and overpriced. Many other restaurants on property have great steak.
Flying Fish is my favorite restaurant that I have tried so far, and the location on the Boardwalk is a lot of fun.
In truth, every restaurant has its fans and detractors. I agree with @SallyEppcot about thinking about location and choosing that way. Getting around property can take a lot longer than you expect!
Oh, and I almost forgot - Hoop Dee Doo Musical Revue!! SO much fun, tasty food, and a totally different dining experience!