So, this is the patch with all of the Deathwing content and other changes that are "paving the way" for the Shattering.
I'm still collecting more information on what WASN'T announced in their official patch notes, so I'll have more soon. But, it appears that most of the official changes are just bug fixes.
Here's the undocumented stuff though not found in the link above:
- One big change will affect players working on the [Insane in the Membrane] achievement. New changes are now in effect so that the [Gordok Shackle Key] no longer drops, and the Gordok Suit quest only rewards 75 points now (instead of 250 per turn in). So, if you've just gotten your Bloodsail Admiral title and were planning on building up your Steamwheedle Cartel reputation - you're pretty much screwed now until after Cataclysm. Stay away from Cartel cities in the meantime. :)
(Note: You can still kill Bloodsail Pirates at a rate of 5 rep per kill (for Booty Bay, 2-3 rep for other cartel members), but you'll lose Honored reputation. However, once you've obtained Honored for the first time, it already counts towards the Insane achievement.. so it doesn't really matter that your reputation with them decreases again unless you want to stay honored with the pirates.)
- The [Insane in the Membrane] achievement still includes the Exalted Shen'dralar requirement, however it will officially be removed on 4.0.3a when the Shattering occurs.
* Update: I'm told that the Shackle Key is still dropping, so I'm not sure if the change has been made yet. Right after the servers (US realms) went live, 3 guild members ran DM separately about 5-7 times without the key dropping which they noted has never happened before. So, there are some conflicting reports on this and it would probably be best if you just test this out yourself on your own realm.
- The new patch also contains more data for the various landscape and zone changes for the upcoming Shattering event which will take place within the next couple weeks.
- Wintergrasp tenacity has now been removed so there a limitations to a 1:1 ratio now. So if your server has an overabundance of Horde PVP players, you'll notice that you won't be able to join WG much anymore (it will be locked out and you'll be placed in queue.)
- Rewards for Random Heroics are now displayed properly in the LFD window.
- Shift-click buying of those Inks from Jessica Sellers is finally working again. It's been down for over a month and a lot of right-clicking was needed. =]
- It doesn't look like there are too many other interesting changes (that's all I'm really interested in). [Glyph of Mage Armor], [Glyph of Long Word], [Glyph of Vanish] and [Glyph of Armors] are all still broken too - they're still not available from the trainers and they cannot be researched. And there's a Cataclysm Cinematic available at the Login Screen, however it can't be launched just yet. Video is going to be streamed now for the Digital Purchase users.
I was hoping for more, but this recent patch is just a whole ton of data/maps/textures/sound/etc for the Shattering event.
4.0.3a is currently on the PTR, so you can see most of the aesthetic changes yourself. Old World Flying will not be live Cataclysm however, and I'm not sure if Archaeology will be implemented Pre-Cataclysm (* Confirmed: Archaeology cannot be trained in 4.0.3a, will only be available after Dec 7.)
[Glyph of Mage Armor] is working again on the PTR, so if you have any left you should sell those as quickly as possible before the next patch hits and Scribes will be able to start making them again. You can also sell a bunch for high prices that first week before other Scribes clue in too.