LOL! I never noticed that.
I thought Kristen Johnston would have a huge career after Third Rock, but she kind of disappeared. Maybe because of the problems you mention. I was pleased to see her pop up on the HBO show The Righteous Gemstones last season and this season.
Who'd a thunk that the breakout star to emerge from the newcomers on that show would be the youngster JoGo, Joseph Gorden Levitt? (Though I believe his character was actually the oldest member of the alien crew, by a long shot.) A very talented actor/writer/producer with some interesting side projects.