The issue with the Mastermind explanation is that it creates a new origin to the Void, one that has him only existing after everyone begins to remember Sentry, suggesting that the Void wasn't Sentry's nemesis during the glory days (before the wipe). It removes one of Sentry's more interesting plot points, the fact that Sentry and Void were considered to be two distinct people for most of Bob's career, where they duked it out like Superman and Lex Luthor and everyone just thought Void was another super villain. Then, one day, they discover that the Void and Sentry are the same person. GASP! It's the twist of the century! Sentry and Reed then create a device to save the day because the Void is also becoming too powerful and killed a ton of people. The device makes everyone forget Sentry, including Bob himself. This story is way more interesting than the Mastermind version, as I think we all agree.
That's what actually happened in the comics. What I'm asking is, if we were to retcon Bendis' Mastermind explanation and return to the original mini, basically throwing out the New Avengers story you're referring to, how would we want to explain the way everyone remembers him? How does Sentry return to the world if the reason he was forgotten is the Confluctor?