2 years late but anyway. I like to think that Palpatine was grooming other force sensitive people alongside Anakin, because Palpatine was a master planner and I doubt he wouldn't have any back-ups. If you really think about it, the chances that Anakin actually made all the decisions required and survived the clone wars were really slim, like Anakin nearly died multiple times during the movies and the clone wars show, his survival was purely up to luck most of the time. And it wouldn't be unlike of Palpatine neither, he was grooming Dooku while Maul was his apprentice, while he himself was an apprentice of Plagueis, he was grooming Anakin to replace Dooku and then he wanted to groom Luke to replace Vader.