I believe AS is trying to standardize their first and premium number of seats to 4 rows of First and 5 rows of Premium on all aircraft. In order to make this possible, something has to give. That give is legroom in the back of the aircraft. The over wing exit rows 16-18 will be similar to Southwest 737-8's. 18A and 18F will have infinite leg room at the cost of an in arm seat tray. Can you store your personal bag under seat 16A and 16F? This will make choosing 17C, 17D, 18A, and 18F on a 737, a box of chocolates. You never know what you are going to get.