I don't see any need for two concepts. Why not
ask the user
whether a new folder should be a sibling or a child, in the
same way the old version let's the user decide whether a new
name should represent a Folder, Glossary, Page or Resource?
Instead, ask "Child Folder, Sibling Folder, Glossary or Resource"?
yes, that would be more clear for a user. Maybe it's better to just ask:
"Page, Glossary, Resource". Because the term "page" is more clear
than
"folder" in this context, and a sibling page to the current page would be
created in the parent of the current page, not in it, I think. "Sibling
folder" might confuse users.
So a Page should have the possibilty to contain some children, like it does
now in SW2.
kind regards,
David