As soon as they left it up to the general public, it became a popularity contest, and Griffin is one of the most popular new players in the NBA today, (for obvious reasons). The car dunk was one of the easiest dunks ever, and like Dwight and his stupid cape, (whcih wasn't even a dunk), it was all about props.
McGee should easily have won this, but like I said, it was about popularity, not skill. If they're going to involve the general public, it will walways be about who they like the most, and not talent or skill. They need to get it back into the hands of the people who know best ... the previous participants.