Did the “Natural feature” rejection only show up after the appeal? I believe that appeals reviewers can use rejection reasons that the community can’t choose.
Edited to add this link to a comment from Aaron:
Edited again (lol) to say that I think the appeals reviewer was trying to tell you that they weren’t convinced that this waterfall was interesting enough to search out to visit, and that a sign would help indicate that it is. A sign would also make it clearer when you have reached the Wayspot.