In recent weeks two things have made news for Warcraft; the recent policy change towards add-ons and the roll out of patch 3.1.
From what I have read and listened to, many feel the main issue with policy change towards add-ons is a direct money issue. People seem to think Blizzard main issue is that add-on makers were making money off their product and that Blizzard should have greater control over this. With Patch 3.1 coming out this week and all the excitement about Ulduar and all the new content; a large number of players have seen what I feel is the more important reason why Blizzard changed their add-on policy. Add-ons cause technical issues for Blizzard and players. With each patch change add-ons stop working and create new errors; meaning that all add-ons need to be update to work with a new patch. Now this is not really a problem for many add-on users and the same goes for the creators of those add-ons (though creators have less reason to update add-ons now), but for Blizzard this is very important. Imagine the numbers of messages game masters got this week because players were getting error messages simply because their add-ons had not been updated. Remember when Wrath first came out and Quest Helper would not let you log on if you were in Dalaran. We can be very sure that game masters had to reply to a ton for messages telling player to turn off Quest Helper or this is a bug caused by the add-on you use. Blizzard should not have to be tech support for the add-on makers but this week more than ever they are. This is why I think Blizzard took steps to change their add-on policy, so they would be getting fewer add-ons in game to cause errors that they would have to spend time addressing.
As part of the add-on policy change there have been a number of additions in both 3.1 and even 3.0; taking features from add-ons and putting them directly into the game. Omen, Quest Helper, and Atlas are some explains of Warcraft taking what add-ons did and putting them into the game. With 3.1 the threat meters have been improved to the point a player can go without Omen. There has been improvement made to tracking quest information, though this is still not at the level of Quest Helper and likely never will be. Much was made of the Outfitter style feature that was going to be in 3.1 and I will be interested to see how that works once they get it out in the next patch.
Since they have shown themselves willing to take from add-ons in such a way we can now ask what add-on would you like to see be put directly into the game? For me it would have to be an improved UI add-on, recount or inventory tracker.