I think what Pardo is proposing will just make the game feel sort of arbitrary. What if I'm not in the mood for a tougher challenge tonight? What if I am, and the game hands me someone of lesser skill? That guy who just wiped the floor with you? Was that player way above you, or did you make a blunder? Did you just win because you're improving as a player, or the matchmaker threw you a newbie? You can't face that opponent again and find out, because they have vanished into the crowd and the game is going to give you another random name to play against.
The other thing that gets lost in the random matchmaking games is the sense of community. If you play with the same group on a regular basis, you get to know other players. You develop respect and trust, and the ability to gauge your performance against a familiar opponent. In a game with random strangers, there's little room for community or culture. Social networking is all the rage these days, and I think a bit of that thinking would do wonders for competitive online gaming. Let people associate and form groups based around common interests. I'm not talking about forming clans (which I imagine they'll have) but more about letting people choose "hangouts" where they can look for players. Let players associate themselves with each other based on their love of playing Zerg-only, or Dr. Who fans, or people from Chicago, or players over forty years old. Offer them community tools so that they can make whatever sorts of distinctions they like and seek out others with similar interests. Maybe some players like strutting, smack-taking brawls, and other people like casual, friendly games. Some people want a rugby culture and others want a checkers culture. Everyone will have more fun if they can find other people that want the same thing.
A game that gives people convenient ways to form ongoing relationships will naturally have more personality and be more pleasant. People are more likely to be good sports towards you if they think they'll see you on a regular basis. If everyone you meet is a random encounter, you end up with the gaming equivalent of "road rage".
Note that I'm not really criticizing Pardo, or even StarCraft 2. I realize the game is still a work in progress. I am saying that community tools would improve these online games in general. As PC games moved away from the dedicated server model (not that RTS games ever used dedicated servers) we lost a lot of useful features. Those features could be brought back and even improved with something like Battle.net. I think the best system would be one where people can direct their own matchmaking instead of having an algorithm try to guess at what they will find fun.
Then again, maybe I'm just mad because Battle.net will never be able to find a suitable StarCraft opponent at my level unless Blizzard lifts their strict "no chimpanzees" policy.