The changing of Sylar does harken back to that possible future where President Petrelli is actually Sylar and goes homicidal, killing Claire I think.
My problem with the mind-trick is that we'll spend at least several episodes next year wondering either is Sylar really redeemed or when is he gonna start killing people? And neither option appeals to me.
And it was beyond stupidity not to tell Claire that her bio-dad was dead and replaced by his killer. Do they think they can keep her from going to say hi to the man she thinks is Nathan Petrelli?
I've heard that Heroes has been renewed; but I fear that next year will be the show's last, unless they really step up the storytelling.