"(Hopefully this doesn't read too harsh, it's been a tough Monday. ;) <3 <3 <3)
Our intent is not to have a game with broken balance in an attempt to sell an expansion. That should go without saying. It makes me sad it isn't.
Our intent is also to not apply knee jerk fixes based on the first few weeks as understanding of the game and strategies are still in flux. The game is young, and we don't feel that it would have been helpful to progressing peoples understanding by throwing in tons of fixes based on flavor-of-the-week (or day, or hour) strats.
We see a lot of variation between the regions. Making a change for how NA players play may be completely ridiculous for how KR players play, and actually mess up a balance there. For instance 10 of their top 20 players are zerg. So that's one place where we have to be mindful and careful and attack balance issues with great prejudice.
That said. There are balance changes coming. What everyone was seeing in beta with tons of quick balance changes are because it was in beta and we feel we can get away with throwing out a lot of 'we think this may help' type fixes. With a live environment we're not going to throw stuff out there unless we're pretty sure. We've played. We've looked at data. We've looked at each region. And then we act. Which isn't to say we may not be wrong from time to time, but it's a more measured approach than beta players may be used to or expecting."
Source: Battle.net Forum: Blizz refuses major balance fix til expansion