Williams winning made sense in the moment. Two reasons why, and none of them are about game 7 for me, since both Kopitar and Doughty were also good there:
Round 1 - Kings down 0-3, dead in water, and Williams was GREAT in the comeback. Two goals in game 4 (and, important goals, both times broke a tie), and 6 points overall in those 4 games in the reverse sweep (to be fair, the other 2 players were great too here, but I think Williams stands out a bit more).
Finals - Williams had 7 points in 5 games. The other 2 were limited to 2 assists each.
The finals is always more important than earlier rounds. Maybe if you look at all 26 playoff games that year as equal in importance, either Kopitar or Doughty win. But I thought Williams winning was fine.