It's a good concept that of course has been done many times but what I found disappointing about this one is, it's a work of fiction, yes and then they made it into a series, yes.
So why couldn't they make something up, why does it have to be that he can't change things, once that occurs it's completely pointless and the viewers has really wasted their time. In a made up story why couldn't he be saved and just for a moment have changed history that would have been cool.