Same thing happened to Valerie Harper in the '80s. She created Valerie and then was fired in a contract dispute. The show then became The Hogan Family and continued for four seasons. The Hogan Family was never anywhere as good as Valerie.
IMO, The Connors will be much worse compared to Roseanne than The Hogan Family was to Valerie. The Connors will last one season and then be quietly cancelled.
I always wanted to date Valerie. Such a hip and whip smart little Jewish girl. About as guilty as Honey West or Diana Rigg.