Of late, I've heard Koenig being very reasonable and saying "You know what? we were extras and day players. Bill was the star."
Yeah, he guested on Shatner's talk show and made it clear that he was totally over it. For his part, Shatner was very complimentary and gracious to his guest. It was an excellent interview.
I saw Doohan back in '86, right after TVH had come out. He was slamming Shatner all night and came off as very petty, which is a shame, because he seemed like a lovely and charming man, otherwise. But that bee in his bonnet got the best of him. At one point a girl in the audience stood up and simply asked, "What did Shatner DO to you that you hate him so?"
She got a round of applause. Doohan got testy and refused to answer.