Just from the top of my head, and I could be wrong about some, by the end of 1986, the show had lost...Carl, Larry, Clarice, Sally, Caitlin, Brittany, Zane, Kathleen, Cass, Nicole(?), Jake, Marley. They also recast Vicky, Vince and Donna. That's a huge change in the cast and so many of them were fan favorites.
I also agree about the writers twisting the story to make it fit. It was messy. The good thing was the Vince recast. He had great chemistry with Denise Alexander. I also liked Mary's friendship with Felicia which was dropped when they isolated Denise's character in her final years.
I just finished watching the first set of clips and one stand out for me is Gomez. I forgot about her and I love her.