Love this review. I agree with most of it looking at it as a frequent Carnival cruiser who is new to Royal. I think Carnival does a much better job trying to provide the same experience on their older ships as you would get on the newest. While Royal has "amped" some ships, Carnival has a similar initiative called "Funship 2.0". It has been completed on their entire US based ships. The only exception is the Luminoso they recently transferred from Costa.
I'm currently booked on only Royal because the casino offers are better for me right now on Royal, but I would be open to either company in future.