I think when they started the series, Bae was going to be Rumple's happy ending, but then when the fandom went crazy for Belle and Rumple in Skin Deep (which A&E admitted totally caught them by surprise), they changed their minds and decided that Belle would be Rumple's happy ending. The problem is they don't know how to write for that story - Belle has been written so badly that at this stage I don't really care what happens to her.