Friday the 13th, the 2009 reboot, was not like the fans wanted it to be, from many points of view. One of the main criticisms brought to the film was that it lacked (for most of it) the iconic hockey mask, which became synonymous to Jason Voorhees (much like the glove represented Freddy Krueger and the chainsaw represented Leatherface).
But, at the same time, this was also one of the things for which other fans appreciated the Friday the 13th reboot, since it presented the character from a different perspective, thus giving the viewers an idea of Jason as a whole.
As it was said, Jason wasn’t just the average hillbilly, but also one that lacked any identity whatsoever (being, basically, a castaway since he was a child). So the hockey mask was his way of developing such individuality.
In a way, when the director has him finding the said mask, it can be said that Jason Voorhees becomes aware of who he is and of his destiny. However, him wearing a sack on the head was the road that led him to that point, which is as important as the finding of the hockey mask in itself.
This comes in fact as an origin story not for Jason Voorhees, for when he was a child, but as an origin story of the killer that everybody loves to see just on screen.
Of course, such an idea to be brought on screen probably needed more attention from both the writer and the director in order to have a full effect. However, the idea still remains, no matter how bad it was put on film.
But, as said, the film probably wouldn’t have worked anyways. After all, as implied before, Jason is his mask, as much as Freddy is his glove. The horror of the film and the pleasure of the audience don’t come by seeing an anonymous killer running rampant among promiscuous teenagers.
The horror and the pleasure come from seeing that anonymous killer wearing the hockey mask. This is what separates him from the rest, and not the gruesomeness of his kills.