The Tournament of Champions is indeed a round robin follow by a double elimination, but everything else is a simple single-elimination. As for letting skill shine in duelling, there's nothing preventing you from duelling with your opponent before hand if he's so inclined. In fact, I'm guessing most of the likely victors will probably have duelled each other multiple times already. In addition, none of these are simple melee duels- which again changes the game.
I do remember the days of one-hit kill duels in cRPG. Those were fun. I think it was like that due to the massive wpf we all had.
P.S I'd share my caponata with you, but alas.
@Earthdforce: if you both run out of ammo for the Shootout, the duel is a draw.
@Centurion: I'll see about that steam group.