I still think the severity of the penalty was a reaction to the injury more than the hit itself. The fact that they had to call it charging after reviewing it to justify a major tells me they overreacted in the first place.
I was thinking about it and I'm not sure the review can change what the actual call was, I mean, there was very clearly head contact, so I can't imagine they moved away from calling illegal contact with the head only to call it a charge, given he didn't leave his feet, and coasted into the hit.
The end result clearly played into them calling it a major, no question there, had he bounced back up and been fine it's probably a 2 min minor, maybe nothing if they didn't see the head contact until doing the review.