Legacy can take a lot of power. The format sees play with some of the game's most powerful cards. But regardless of how powerful your cards are, you need to be able to cast them to take advantage of them. Much like in Modern, Grief prevents players from being able to do that.
While folks in Modern use narrow cards like Malakir Rebirth or Ephemerate to take advantage of Grief's manaless evoke ability, Legacy has Reanimate and Animate Dead backed up with protective elements like Daze and Force of Will. Various flavors of Reanimator strategies have long been viable in Legacy, but they have been generally kept in check by the strongest anti-graveyard cards ever printed being widely available. Grief presents a threat that synergizes well with reanimation effects while being able to attack the hate cards opponents would traditionally present.
Simply put, Legacy has not been able to self-correct to handle the powerful combination of Grief and Reanimate. With Dimir Reanimator's ever-growing metagame share, we've decided to ban Grief in Legacy.
Again, as in Modern, we considered a handful of other cards for this round of changes. We looked at the new Eldrazi deck, featuring several Modern Horizons 3 cards, and talked a lot about Psychic Frog . However, Grief and Reanimator is such a large part of the current Legacy metagame that we wanted to make the clear and obvious change to the format before making further changes. Specifically, Grief and Psychic Frog are featured together in Dimir Reanimator. Psychic Frog also appears in various Delver shells, but it stands to reason that it should have a smaller metagame presence once Grief has been removed.
