I think people need to stop thinking about the past.
Don't know why people are so against adding new members to the current cast. However, I think it is good to add a new member to the show because a new member will add new stuff to the show. I mean Kwangsoo is not going to come back to the show as a fixed member, but maybe as a guest.
It's the same thing as when Somin and Sechan adding it to the show. They just hate them for no reason especially Somin.