Seatguru and similar sites frequently warn users that exit rows are narrower (due to fixed armrests containing tray tables), row 31's proximity to the lavs and the intrusion of the emergency slide. These warnings border on the absurd, given that these seats are some of the best coach seats ever.
During the MRTC era, row 31 had an additional 6-8 inches, which allowed for seeing out the window (which is now row 32's window). Now, the slide does intrude some, and there's no window. But I've always been able to place my carryon at my feet, pad it with a blanket and pillow, and viola - an ottoman. Place the carryon in the overhead for takeoff and landing but use it to stretch out during cruise.
Enjoy 31A. One of the best coach seats of all time.