This card seems incredibly well designed for its purpose. It appears they were trying to incorporate the combo fighting Power of force of will into modern without allowing people to use it to protect combos. They did so in a very narrow way.
I'm not sure this card actually matters at all for vintage because with excess to four forces of will, how many decks actually need another four cards to protect themselves from broken combo? What decks in the current meta have a huge problem dealing with combo? Those decks might have some number of these in the sideboard