Valve Recently added Highlander mode to TF2. Oddly, it seems like all the games media are treating this as a big deal, even though Valve buried the announcement in their patch notes. Doubly odd, since the way it's implemented is no better than the system already in place in fan-created mods.
There's no system for selecting a class "preference", or arranging a trade in a means other than talking to the person you'd like to trade with. This could theoretically lead to players ending up with classes that they simply do not know how to play. That may be the explanation for why people tend to be idiots when they're in highlander games. The typical highlander game is like two children awkwardly fumbling at each other.
Despite all this, I Love Highlander. I like to think I'm good at most every class, so I don't mind being pigeonholed into the class no one else wants. (Especially since that class tends to be Medic, who gets all the points.) When you kill someone in Highlander, it has real significance. When you kill a medic, or destroy an Engie and his sentry, you have pushed through a major victory. You know that you won't just run into another sentry nest around the corner for at least thirty seconds. I wish tournaments were held on highlander format. It'd force nontraditional strategies and maneuvers. The fact that half the classes of TF2 basically don't participate in tournaments irritates me.