Yeah I wasn't convinced either of their overall chemistry so far. It's been a lot of desperation from her and lots of boring dumbness from him. He's definitely my least favorite Bridgerton brother and little Gregory's only had five lines so far, so..
I guess I'm not that excited (never read the books, sorry) because Penelope has already taken up so much screen time in season 1 and 2, and the second season in particular really put me off the character. Same with Colin who is just so, so boring imho. Season 3 better be sensationally written for these two, or include lots of scenes of Anthony and Kate.
Edit: as for the Duke...I think production really didn't think this through when they let RGP sign on for only one season. He claims that both he and Shonda think they left off the character in a good place with that season 1 ending, thus there is no need for the Duke to return or something. I guess they really want to pretend that Daphne raises her son on her own and that her husband is too busy to go even to his friend's wedding who also happens to be his brother in law