By the fourth season (http://jacksonupperco.com/2017/10/03/the-ten-best-newhart-episodes-of-season-four/) when Michael and Stephanie were a couple, it's debatable between whether or not they were annoying and grating. Also, it's pretty safe to say that Stephanie by this time, went from being an actual person who was rich, spoiled BUT realistic, to just a caricature of a wealthy brat.

I thought it got much better when Kirk left.

Michael was a character who was best in small doses. I liked Kirk and missed him.

The shows ratings got better when Kirk left.