I don't think Primal Groudon is worth of S+ tier, while it is very good, it hasn't the same power and variety of roles as Arceus. Since AG allows to use as much Arceus formes as you want, using a support Arceus forme has no opportunity cost. Primal Groudon support set is inferior to an Arceus one, because Arceus has Will-O-Wisp, Magic Coat, Recover, Defog, Perish Song, Extreme Speed...
Lack of recovery hurts it a lot. So Primal Groudon better suit for offensive use. But the fact it is slow and can't hold an item makes it easy setup for Darkrai. It wants Swords Dance and Rock Polish to sweep effectively, but getting these two boost is easier said than done.
Lack of recovery hurts it a lot. So Primal Groudon better suit for offensive use. But the fact it is slow and can't hold an item makes it easy setup for Darkrai. It wants Swords Dance and Rock Polish to sweep effectively, but getting these two boost is easier said than done.