I would like to add my perspective to the Japan/Alaskan cruise. My wife and I are mid-fiftyish 3 star mariners and are on the Westerdam for the the last leg of the cruise from Yokohoma to Seattle. First off I'd like to thank the OP for the excellent posts and insights which we used to plan for our stays in Kyoto and Tokyo.
Also, the post on the change of itinerary with an overnight stay in Yokohama was invaluable. Since we knew that we had another full day in Yokohama we were not rushed on embarkation day to visit all the touristy sites in one go. We took an early train from Tokyo station ; dropped off our luggage at the Yokohama cruise terminal at ~10:30 and leisurely explored the city for a few hours noting that we had a full night and another day in Yokohama to visit the sites we missed on the first day.
In contrast to some of the posts on this thread I find that I am at times overwhelmed with activities choices on the Westerdam. As I am not a night owl, I cannot comment on post 10pm entertainment since I'm usually back in my cabin for some night time reading and relaxation.
Some of the daily activities include morning talks with our ever present cruise director Rachel and special guest(s) ( ex. Head chef, engineer, entertainers, hotel manager, HAL cadets etc.) The talks were very informative and the floor was always opened to questions.
Another well attended event on the World Stage were lectures from Andy Fletcher on the Universe and everything. He touched on topics like Einstein, Newton, Gravity, Quantum particles, chaos theory and much more. Bridge lessons, orgami folding, ping pong, pickle ball, fitness classes, mah Jong and of course trivia and others were always available everyday.
A pleasant surprise was having the Captain introduce his senior staff on the 2nd night of the cruise before the evening show. He also presented a talk a couple days ago on the World Stage and took some hard questions especially on itinerary changes.
We did have a couple of issues with our stateroom which were resolved efficiently in a few days.
Overall, this has been an excellent cruise and we would not hesitate on taking another HAL cruise.