In my opinion the hit is analogous to an inadvertent high sticking penalty. It doesn't matter whether or not a player meant to hit a someone in the face with his stick, all that matters is that the player was not in proper control of his stick. Every high stick the referee sees is called, regardless of intent. I don't see how a hit to the head should be ignored based on intent if high sticking isn't.
What I would like to see, however, is the implementation by the NHL of some type of concrete rule regarding the length of suspensions assessed for hits to the head.