Hey - thank you for the detailed comparison.
I was noticing the same thing about entertainment venues.
Here is the motivating factor that cruise lines are moving towards and I think you are REALLY going to see this a lot mor moving forward. You notice Royal Caribbean's Project Sunshine has not been detailed at all yet, but consider this...
The biggest waste of space on a cruise is big rooms that are only used at certain times.
A main theater is usually only working at night when there are shows - the same with a big disco which is only used at night.
They are doing away with that aft lounge on Destiny which used really used rarely except at night (and rarely full).
You are going to start seeing big rooms being used all day long on ships - and no rooms that are shuttered 12 hours/day. This cuts down on cooling energy costs and leaves room for more cabins. I am surprised to see you say the dining room is getting smaller, but perhaps they will be announing different nighttime dining options in the future(?)