Perhaps this is the smallest update made to the Public Test Realms of the Patch 4.1 but we didn't want to miss the news. A few changes to classes and you're done. In case someone is scared to see the change to the Druid, it should be noted that this was already commented on in the previous update, but now they put numbers on it.
Quote from: Blizzard Entertainment (Source)
Death Knight
- Blood
- Death Strike now heals for 20% of sustained damage, up from 15%
Druid
- Feral
- Swipe (Cat) now deals 670% of weapon damage, up from 335%.
Guerrero
- Weapons
- Improved Slicing now reduces the global cooldown of Slicing by 0.3 / 0.5 seconds, up from 0.5 / 1 second.
Do not stop seeing the full patch 4.1 notes.