What if somebody stole some thing from Harry Potter and have Sauron do one of those possessing things? He could possess someone who is among the evil still in ME and then work through that person. It could one of the Blue Wizards and then they discover the secret of the Rings of Power and make like three more

. Then there would still be that Quest element, only they would have to get the Rings before they destroyed them. Or maybe the good guys could find the Rings' secret too and make some of their own.

Whew, enough brainstorming for now.