On the rides front, I think they could use projectors plus trackless ride systems to make rides that change throughout a cruise. Monday you get a mini Rise of the Resistance, then Tuesday you get a mini Runaway Railway. Because the projectors can make everything dynamic and because the trackless ride systems can move dynamically, you have total flexibility to create new rides, continuously.
A trackless ride system would not be very space efficient, but given that you can make it dynamic and change it every day (or even multiple times per day), you have the potential to create a premium experience that will be very heavily used.
And on the pool decks, I think there's room to make AquaMouse have multiple lanes if you have wider ships. If AquaMouse were on an Oasis-class or MSC World-class ship, they could have two separate AquaMouses, one on each part of the Y at the aft of the ship, for instance. And each could have a slightly different dark-ride experience.
And I love the idea of "Club 33" branding for
DCL Concierge. It provides a place where you can escape all the hustle and bustle to your serene Concierge sundeck and restaurant.