I have an idea about formal nights. Let me first preface this by saying that I myself do not dress very formal on formal nights. But I know people who really like dressing up, especially women. It's their time to take out that favorite gown, the jewelry, the fancy hairdo. Some families take it as an opportunity for that family photoshoot in nice attires. For some it is a change of environment from their otherwise "come as you are" events. I think there is still a good percentage of people on the ship who like these formal nights. Being seated next to someone in a tank top and shorts on formal night somehow takes away from that expected ambiance of a formal event. (Yes, I was seated next to one, but I didn't mind)
Maybe Royal can designate a section of their MDR, especially on bigger ships with multi-level MDRs, to be formal attire only on formal nights. It will be by reservation only and the dress code will be strictly implemented. That way, the guests who are wired to enjoy formal events can have their good time and everybody is happy. I know in the past, when formal nights were still "strictly" observed, formal attire only at the MDR and casual attire at Windjammer. But I think that is not doable anymore.