It needs to allow you to draw just ONE card per turn. Any engine that allows for near infinite draws is broken, in ANY GAME.
Either make it one card per turn or remove it altogether. EVEN MAKING IT 10 mana would still be overpowered. Even if you made it a 10 mana 1/1, it still would be broken. THIS is something we all can agree on. The game is so one sided with it as druid there is no real counter to stopping it since another can be drawn with a spell! (imb4 someone says dirty rat, you gonna have 2 rats in hand? rarely if never).
So yeah… NERF ASAP!