We did the 'assigned dining partners' type tables for many of our early cruises. We met some fabulous people and very much enjoyed their company. Then we had a few 'duds' as you call them. One was so bad we found ourselves avoiding the dining room. That did it!
From then on, we requested and have always been assigned to a table for ourselves.
We can meet all the folks we want when we are out and about.... in lounges, at the pools, at private cocktails parties etc