Biggest enhancement to newer ships
One thing I haven't noticed is people mentioning minor enhancements made to newer ships of the same class.
I sailed on Wonder the other week and noticed what, to me, is a big deal. They use magnets on the bathroom door instead of latches.
To me this is a big deal because, when sailing on older ships of the same class (Oasis and Allure), when the boat was rocky I'd always be annoyed by the clicking of the bathroom door ever so slightly moving around. Now, because they use magnets, nothing ever moves.
Is this a small thing? Yes. But this is definitely a consideration for people that may be light sleepers or just have problems with annoying noises.