I absolutely recommend you get a suite. The Mermaid rooms are cute, but way too small. Even the toilets are very short. The beds are too small.
Because of the two bathrooms and separate bedroom, we always stay in the suites now. Also, having the little kitchen area is a real plus.
We prefer Lion King or Cars over Nemo. The last time we stayed in Nemo, we were in the back, close to the water and it was a long walk to unload/load the car or to go to the food court or busses. If you luck up and get in the front, it would be fine.
We will be there again in May. Lion King is our suite of choice. Our son and his gf stay in Mermaid. They have lucked up the last three trips and got a king room. By staying in Lion King, we are close to them.
FYI none of our cell phones work in the rooms. We have to go outside to use them. We have four different phones and carriers. The wi fi is really good.
They don't lock the exit doors during the day so you don't have to use your band to get in, which is helpful when you are bringing in your luggage or bringing food or drinks from the food court.