You'd think this would cost more than it does, given the effect it has, but the drawback of affecting the opponent's creatures as well is supposed to drag the cost down. Unfortunately, Coat of Arms usually sees play in decks built around swarming the board, and as such, it greatly overpowers the opposition. It can turn a board of 1/1s into powerhouses that should never be that powerful for how easy it is to generate tokens and play this passive buff. Much hatred for cards that enable easy mode.