I was on the Oasis over the New Year, and I believe the ship is still in excellent shape. I am very detail oriented and I have noticed the cutbacks, but it was still a great time and bang/buck on a vacation.
The Oasis class stands out for entertainment. The Aqua show is probably the best of the fleet. Cats had good quality performers, but they still have to work with a shortened version of the musical which is hard to deal with in the first place. The comedy club was fun as usual and the ice shows were average, but nice. The cutbacks in the MDR are noticeable, but I could usually find something descent to eat. I usually have a plan to avoid most crowds (New Year's Eve was an exception) and I do not typically like buffets so I did not eat in the Windjammer once that entire cruise. Over the years we have learned to add in a specialty dining or two to change things up and 150 has yet to disappoint. I am in your same age group, but I have been sailing Royal (as well as several other lines) for 30+ years. Some of the negative reviews are people going in looking for something to complain about because it isn't what it used to be. The long story short is the adaptation of specialty restaurants (and ability to uncharge) has decreased the MDR food quality and service, but the entertainment is significantly better than what it used to be in decades past. One word of advice, if your cruise visits Nassau just stay on board and enjoy the activities on the ship.