To put it in another way, a show that became almost unwatchable in its latter seasons due to it stopping its focus on the topic/premise and theme of the show in favor making the personal lives of the characters the central focus for virtually every episode.

For example, what if your favorite procedural show (like Law & Order, NCIS, CSI, Criminal Minds, etc.) went from being about outsiders who solve crimes to being an inter human drama where said outsiders are now the constant targets for the criminals?

Law & Order SVU. The show started out where it was about solving special victim crimes. Occasionally there would be an episode that mentioned a character's life. However, once Christopher Meloni left the show, it became a hard core Mariska Hargitay show. Every season her character Benson had something traumatic happen that took over the episodes. I think now fans only continue watching to see what they'll do to Benson next since she's the main victim.

Will & Grace. The entire last season (of the original run) is nearly unwatchable because of all the drama focused on Grace choosing Leo over having a baby with Will. It totally distracted from the humor of the show.

The Ninth Season of Family Matters(lone season on CBS): The Harriette Recast took place during the mid-season

ELLEN-the entire last season when her character "came out of the closet" (because Ellen DeGeneres did in real life) it went from being a very funny sitcom to the "Ellen is gay" show.