Any ideas why she wasn't featured in the main credits for S2?
I always thought the highest paid actor gets the first starring slot in the credits - or an "And Starring Diana Muldaur as Dr. Katherine Pulaski" at the end after the regular/alphabetical order, or at least a "Special Appearence by"-thingy?
But she always just got the "Also Starring" part when the episodes were already rolling.
It was Muldaur's choice.
The producers offered her a main cast role, but she didn't want it since that meant she would required to be on the show for several seasons. She wanted the freedom that a guest star had so she could take other acting jobs too.