My thought is you run Raven Idol so that on turn 1 you try for another innervate/wild growth/wrath or if you draw it later you want Swipe/Roar. Spells are guaranteed to be Druid specific whereas random minion can be anything. I was missing a 2 & 3 drop so used it turn 1 for a minion and had choice of Rafaan, Megineer Thermaplugg or the Orc Grunt (2/2 taunt). I should have taken the grunt but went with Rafaan, which never got played. My bad there, but still, the card seems to rarely payoff in this deck.
I do enjoy this deck a lot though, it can ramp up so damn fast especially if you get a Naga to stick, but Raven Idol doesn't seem to fit at all. I see Raven Idol fitting in Combo Druid for that 3rd Roar. This deck isn't playing toward that win condition, something guaranteed is more preferred. Perhaps my luck has just been shit though. I seem to always get offered Healing Touch, Moonfire, and Poison Seeds. It's almost comical.