Is this your first river cruise?
Some of the things that made my first river cruise special for me (or at least impressed me):
Umbrellas were provided. They also had limited numbers of walking sticks available.
The availability and accessibility of excursions. I sailed with a group that had different capabilities. My very active friends didn't have to be held back by slow walker me and had their excursions (bike tours, hiking tours, faster walking tours, etc), while I didn't miss out on things solely because I couldn't walk without break for 2-3 hours. For example, at one town the normal bus parking lot required 64 steps each way. They had a small van for the few of us that couldn't handle those steps to take us directly to the town. That same day, one of my friends had work to do that morning, and the cruise director made sure a bicycle was held back for her so she could join everyone once she was finished.
Of note, my friend was a travel agent and it was the day of the yearly Princess one day sale and she had a list of bookings to make. The passenger wifi wasn't working well on our cruise, and so the cruise director arranged for my friend to have access to a computer with better internet access so she could make those bookings.
We did the Chef's Table two nights, once as just our group, and then another night with some of the friends we'd made onboard. It was worth it in our opinion.
In the lounge in the evenings, the musician would plug our phones into the sound system and play our music for us so that we could dance, which was nice as our group wanted something a little upbeat than his normal playlist.
At the end of our cruise, we had booked a few days in Budapest independently. Our cruise director helped us arrange post cruise transportation, tours, and even restaurant reservations.