I really don't like it. The way its worded almost looks like it was made specifically to shut down dredge. Also stops Reanimate, Snapcaster Mage, Green Sun's Zenith, Natural Order, Past in Flames and Gravecrawler before it even had a chance. I think it's undercosted too. Being colorless, 1 mana and very versatile means it will see a lot of play. Definitely a game-changer in Legacy, I think. In Vintage it will probably be a good thing for that format, although I don't pay much attention to the format.
Referring to the deck that utilizes dredge. It shuts down, Ichorid, Narcomoeba, Dread Return, Ancient Grudge. The deck is almost useless with the cage in play.