I disagree with the idea that the "star" characters were the "glue". In terms of keeping the entire show functioning, it would have to be the secondary characters who were "the glue".Picture Barnabas and Julia and Angelique all performing in front of a stage curtain.....with no sets, no costumes, no lighting. THAT's what it would have been like if all the "secondary" roles were not there to fill in the details of the plots! Main characters need to interact with secondary characters to create stories full of intrigue, suspense, and mystery. Much as we loved them (or loathed them, ) the star roles couldn't carry ALL the weight of a complex story line. They needed all the others to move the story forward. And DS had so many brilliant performers in those "secondary" roles: Karlen, and Thayer David being two of the best......
Harry Johnson. Harry Johnson was, in my opinion, the crux of the entire DS story arc.
For the sake of not spilling the beans here...