We spent a LOT of time at the pool during our cruise.  It was warm, the kids were entertained, and it was so relaxing. 
The coolest part was that the pool was designed so that the water can swish back and forth with the motion of the water.  Didn’t always make for easy swimming but the kids thought it was super fun to get bobbed back and forth.
Next to the pool was the soft serve, pizza, bar and hamburger places.  Walk 20 feet and you have food!
I thought it was amazing that they played movies while you swam.  We saw Princess Bride, Top Gun,

 Mamma Mia and a Billy Joel concert.  Also, at night, they would play movies while you sat on the loungers with blankets.  They brought around pizza, cookies and milk and popcorn while you watched.  We saw Captain Phillips (amazing movie, but an odd choice to play on a cruise) and Gravity.
We have realized that all we really need for an incredible family vacation is the people, a pool, good food and warmth.