Blizzard just released the first patch to the game since they opened closed beta. Here's a list of the patch notes...

StarCraft II Beta - Patch 1 (version 0.3.0.14093)
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StarCraft II Beta - Patch 1 (version 0.3.0.14093)

BALANCE CHANGES

TERRAN
Viking
The armor value for this unit in Fighter Mode has decreased from 1 to 0.
The damage done by this unit in Fighter Mode has changed from 6 (+8 armored) to 10 (+4 armored).
Reaper
The damage done from D-8 Charges has decreased from 40 to 30.
The delay between attacks for D-8 Charges has decreased from 2.5 to 1.8.
Orbital Command
The build time for this upgrade has decreased from 50 to 35.
PROTOSS
Observer
Gravitic Boosters: The cost of this research has decreased from 150 minerals and 150 vespene gas to 100 minerals and 100 vespene gas.
High Templar
Phase Shift: This ability has been removed from the game.
New ability: Feedback - Drains all energy from the target unit and causes damage equal to the amount of energy drained.
Colossus
The building pathing radius for this unit has decreased from .75 to .5625.
Mothership
Vortex: The energy cost of this ability has increased from 75 to 100.
Vortex: The target radius of this ability has decreased from 3.0 to 2.5.
Temporal Rift: This ability has been removed from the game.
Wormhole Transit: This ability has been removed from the game.
New ability: Mass Recall - Teleports all of the player's units in the target area to the Mothership.
Nexus
Chrono Boost can no longer target allies.
Gateway
The build time of this building has increased from 50 to 65.
ZERG
Infestor
Fungal Growth: The damage done by this ability has decreased from 48 to 36.
Fungal Growth: This ability now prevents affected units from burrowing.
Neural Parasite: Functionality changed - The Infestor now channels this spell, which lasts 10 seconds or until the Infestor is destroyed. You can now target all units with this ability.
Terran Infestation: The ability’s energy cost has reduced from 50 to 25 and Infested Terrans now spawn 1 at a time.

BUG FIXES

Addressed an issue causing people to receive an “Internal Battle.net Error” message with their game client.
Muting your microphone will no longer cause your microphone to be turned off in the operating system once the program has exited.
Please note that the voice chat functionality has only partially been implemented. There are many known issues with voice chat that we expect to address in a future patch.
The “Medium” graphical settings were reconfigured to work better on appropriate machines. The video settings “auto-detect” functionality has been reset as a result.
Added a frame rate limiter to the game menus to prevent some graphics cards from running at higher frame rates than necessary.


So why is this significant?

Because Blizzard is listening to the players. We've noticed several unbalanced mechanics and reported it. We've lemented that certain units were either not feasible or too overpowered in gameplay. And they made intelligent changes. Changes that are starting to make this game's balance as good as Starcraft I is currently balanced.

SC2 still has quite a ways to go before it gets as evened out as SC1, but it took years to get SC1 as balanced as it is now. It's looking like Blizzard has learned from the past.