The individual who enacts the curse has to kill the thing he/she most loves; I don’t think Rumple could do that. If this curse really did put an end to all other curses, perhaps Rumple thought that would make it impossible for EQ and others like her to destroy people again; it would also make him a human again; and it would mean people would have to turn to each other instead of magic to solve problems. All around, it seems to be a good deal for everyone if magic is replaced by free will and love.
I wish I had an inkling as to how Baelfire will return. I’m just hoping that it happens, and that we don’t get a Sun/jin resolution.