My Mom and Aunt (83 and 81) did the Glass Bottom boat last week on our cruise and loved it. I hadn't suggested it because I'd seen so so comments on other posts but they found it in the Navigator and booked it themselves.
Whether it's boring or not may depend on what you expect. They had done glass bottom boats in other places and enjoyed them. They enjoyed seeing the variety and quantity of fish and they definitely aren't snorkelers...not even sure they own swim suits...so this was a way they could enjoy the reef.
Whether you like it or not depends on what other activities you like and your personal tastes.
While they did Glass Bottom Boat, we slept in and then went to Serenity Beach. I have the sunburn to prove it!