Glad to see people are still excited about this show. I'm not a huge fan of some of the stories, Benedict and Francesca in particular, so I'll probably skip those seasons. I'm super excited for season 4 though as the 4th book is the best in my opinion.
Penelope is my absolute favorite character in the series. I don't remember who said it earlier but I'm disappointed that they took away some of what her character's essence is. She's not the type to confront people so the whole blowout with Marina over Colin was weird to me. It's also weird that they already outed Penelope as Whistledown because that's such a huge part of her story, and part of what makes me love the 4th book so much was the journey I took to figuring out Whistledown's identity too.
SLIGHT BOOK SPOILER BELOW
As for the whole thing where Colin/Marina almost get married, I think the show was trying to give him a reason to leave the continent for a while since in the books he leaves for like 10 years, or something like that, between Simon/Daphne's story and his own. Without the show watchers having context for him to stay away that long, and the depicted obvious closeness of the Bridgerton family, it seems like they were trying to give him a reason to be out of the picture for that long.