That's what would have made it interesting. What happens when the galaxy is ruled by a tyrant who isn't a strategic genius like Palpatine, but a myopic and often self-destructive young man who can't get out from the shadow of his family's legacy? It would have finally been something different than the Empire-lite that the First Order has been this entire trilogy. I don't actually have a problem with the reveal itself, especially if you subscribe to the theory that Palpatine used the Force to impregnate Shmi Skywalker. I just don't think we needed Palpatine physically present in this movie. The prophecy was announced in The Phantom Menace and was ultimately proven accurate; Anakin was the one who brought balance to the Force, by killing the (original) Emperor.