A couple days ago, a hotfix made it so that monsters 3+ levels higher than the attacking player would not longer resist spells so much.  I have no idea why they chose to hotfix it now (as opposed to months ago or in the upcoming patch), but there it is.

Monsters 3+ levels higher than the attacking player were resisting spells at a greater rate than intended. This has been addressed, and players will now be able to land spells with greater success.

Boss monsters in Molten Core, Onyxia, Azuregos, and Kazzak had their HP increased to compensate for the increase in caster DPS they will see. The reduction in resistances outpaces the HP increase. Overall, this is a positive change which will increase casters' effectiveness against higher level monsters.

Since this change has had a significant detrimental impact on players, we have hotfixed the bug so that players can use their spells and abilities in these situations to their intended effect now rather than waiting until the next scheduled patch.

Blizzard developer Tigole announced that Blackwing Lair and Zul'Gurub will be coming soon:

Blackwing Lair is already on test... only it's closed off to everyone except internal Blizzard testers!

With that said, we're doing our best to avoid a public test of BWL because we know it is endgame content and I am well aware of the "competition" arguements being made. There is a very small chance that we will have to make some of the encounters public on Test but we're doing our best to avoid that.

When it comes to Zul'Gurub, since it's not the top tier content, we'll probably put it on the PTR for a week or two and let people bang on it to make sure we didn't miss anything in internal testing.

To update everyone, Blackwing is basically finished. There are 3 minor things that need to be tuned before we officially lock it out, and we're hoping to do that today or Monday. Blackwing will not go live in the Battlegrounds patch but will come out shortly after it.

The Blackwing patch will need to go on the Test server for a little bit to make sure there are no major bugs but the dungeon itself will be closed. There is other content in that patch as well, so some time on the PTR is a good thing.

In response to player questions and feedback, Tyren has posted a response describing some of the developer thoughts on the rogue as well as describing some minor upcoming changes that will be made to the class.