In short P and O have sacrificed public space on this ship to cram more cabins in. I've never ever been on a ship (in over 20 years of cruising) where there have been such small public rooms, entertainment venues and bars, making getting a seat difficult (especially on sea or wet days). There are too many passengers on this ship for the facilities provided.
The theatre is very poor, it's way too small for the number of passengers and the seats are a joke. I'm a size 14 (average british woman size) and the seats were actually digging in my hips.
The cinema venue is not fit for purpose as you can't see the full screen unless you are in the front row - how ridiculous is that!