Oh, yes, how would I forget this. Even if you do not stay there, the Rotterdam is worth a visit - both for the classic lines of the outside and the stylish inside.
In connection with a sea voyage you might like the hotel New York, locatedcin the forme Holland America Line headquarter right next to the cruise port.
Not only by train but also bus. The bus stop is much closer to the port than the train station.
If you want a guide inside depends very much on your level of interest and willingness to map your own path. I found the guided tours far to short and covering only small parts of the area. The audioguides and (good) guide books you can use for your own discovery cover much more and you can pace your day.
I am sorry to read about your disappointment regarding the ballroom.
Thank you very much for your review including the important "atmosphere was good".
Where is the "loyalty" part in taking one cruise, even if it is a world cruise?
After all it is a loyalty programme.
Maybe Cunard should change the rules from "or" to "and"?