I've investigated Scribus a few times to see if it would be a good fit for improving the playtest drafts of my games, but the lack of a workflow that would let me separate text from layout would always get me frustrated. Things like marking text as bold or italic are really part of content these days, but since you couldn't mark character styles in a way the text importer handled things you couldn't support that. However, your post reminded me to check to see if anything had changed so I looked at the release notes for 1.5.4 and there is an indication that the scripting interface can now do character styles, so I might need to investigate to see if there's a way to get a workflow that makes sense to me.