“Is required”, “has always been”, “needs to be”... seems to me that this is a pretty rigid mindset and you are setting yourself up for disappointment.
Also there is a lot of reasoning I cannot follow you in. Calling Anakin the protagonist of the prequels seems to be wishful thinking seeing how he isn’t even in half of the first movie, Obi Wan is the obvious protagonist of Revenge of the Sith, and the Star Wars OT era basically had three protagonists only two of which were Skywalkers.