I was definitely surprised with the ‘flatness’ of the replace text section when initially setting up my first forum, even though it’s really helpful.
It feels like there’s a spectrum going from passive UI-type text through to active more opinionated text. I think many users assume the latter type of text is written by the forum owner/moderator, e.g. the first message prompt, the user tips, all the stuff that says “civilized”.
I wouldn’t take anything out of the replace text section, but I would—as Manuel suggests—pull out some of the most important active text into an Onboarding section. Otherwise many new moderators end up finding new text they want to edit over the first few months and it’s all a surprise.