I sailed last week from A to B on the Viking Hlin and Kara. I got two notifications from Viking prior to sailing, one about a week before warning me of the low water and potential ship swap and another a couple days before telling me that there would definitely be a swap and that we would embark on the Hlin instead of the Kara. My opinion differs from you in that I think the communication was great. What else are they supposed to tell us? Having been on the ship I can tell you they are doing everything they can and don’t honestly know from day to day what they will be able to do.
As to the ship swap, it was handled very well. At the time the Hlin could get no farther than Cologne and the Kara was in Strasbourg. After our day in Cologne, we overnighted there, and the next day we bussed to Marksburg Castle, then we bussed to a nearby town and got on a day cruiser and did the scenic sailing of the Rhine to see the castes. We got off in Bingen and we’re bussed from there to Strasbourg. The next day was long as well, because we had to bus from Strasbourg to Heidelberg. We felt lucky that we got to go to all of the promised locations and we were able to sleep on a ship the enire time.
My my hat is off to the crew of both those ships, they handled it all extremely well and did the very best they could under the extreme circumstances.
FYI, my friend is on the same itinerary this week and while she still had to do a ship swap, both ships were able to make it further on the river, so the drive time for her was much less then I had last week.