Match Making?

[Hammy]

I don't get how being matched with people of similar skill can be wrong. If you start to win more, you are going to face people of higher skill than before, and if you start to lose more, you are going to face people with lower skill than before. How does that kill competitivity?

Because I also see SC2 as a spectator e-sport, and to make tournaments with players from all three races, you need the top players to be good against all three players.
And making this an e-sport is most definitely one of Blizzards main goals.

You shouldn't expect the ladder to be the end-game here. It's probably only the beginning in blizzard's master plan. If the game turns out to be what Blizzard wants it to be, I'm sure there will be a TON of tournaments going around.
And let's face it, playing in tournaments is a whole lot more fun than grinding a ladder.

The ladder is for practice (getting to play against players that allow you to improve), but it should definitely also be a tool for ranking players in a way that allows you to select all around "top players" for tournaments.

And that's why, although having a ranking for each matchup would help players find equally skilled opponents, the drawback is that players might improve with only one race, and stagnate with the other, hence making them "bad" overall players.