So, who actually benefits from this? The GR decks (Ramp and Aggro both), for example, surely do. But they’re not the only ones – ironically enough, I think the biggest winner here is not a creature, but Unburial Rites and other similarly unfair spells. Take, for example, Frites (the French reanimator deck). Frites does something fundamentally unfair, as do most decks that play from the Graveyard, and it’s kept in check somewhat (at least game one) by counterspells. Well, no longer – even if there is not one single guy that you really want to resolve, like a Primeval Titan, the fact that Cavern exists means no one is countering your Unburial Rites! Even though the card does not interact with spells (which are way more powerful than creatures, as a whole), it’s so good at what it does that it doesn’t have to, because it forces the counterspells out of the format.