Melisandre's rituals thus far have proven to be incredibly effective, even when just using Gendry's blood which were extracted with leeches.
There is no reason to assume the coming battle at Winterfell will go poorly for Stannis. I just wonder what the hell could drive him. He's just sacrificed his only bloody child.
That said, I would much appreciate a season where he and Melisandre are tortured by Ramsay Bolton.
At this stage of the game, I don't really care who wins the game anymore. Daenerys is an utterly inefficient leader, and her idealism has been the cause of many atrocities. My only hope now is that all the Starks don't die before the end. It would also be nice if Tyrion can survive.