A Future of Despair

With a lot of fantasy books there is an element of prophecy. There is an oracle or seer or magic user who looks into the future and predicts utter destruction unless there is a chosen one. The prophecy normally predicts that there will be a backstabbing of some kind and leaves a lot for interpretation. The problem is that the prophecy doesn't normally add much. Most stories are about good versus evil and if the good fails then there is destruction. Why does it being said in a prophecy make it any more important? And throwing in the backstabbing. The author should be able to create characters who are deep enough that the reader doesn't need a prophecy to give them ideas about what the characters are capable of. Instead of creating a prophecy that leaves everything open try taking it another way. Make a prophecy so specific that you make the reader think there is only one way to fulfill it and surprise them. Or make it so the characters fight it the whole way and beat the odds. Just make it original and not the same old same old generic prophecy that applies to all of the fantasy stories that are out there.