Carr only lasted part a year as Peter Taylor, in 1969. He lasted slightly longer as Bill Horton, from 1965 until 1966.
I might have liked Bundy better as Diana, if I had not seen Starrett in the role first. The character's concept and personality changed so much with the new actress, it was jarring. Imagine Archie Bunker going from Carroll O'Connor to Mr. Bean, LOL. (I'm joking, but the "new" Diana was quite a departure from the original.)
I agree 100% about the mid-1970s GH era. After the Dobsons left as headwriters, the bottom of the show fell out and it was a total snore-fest throughout the writing regimes of the Hollands, the Pollacks, and the Elmans. I could barely sit through it. Only loyalty to characters like Steve, Jessie, Audrey, Lee, and Lesley kept me hanging in there. Douglas Marland's arrival turned everything around, however. Within just a few weeks, GH was must-see TV.