Note: This article contains information relating to the World of Warcraft Public Test Realm. Since it is still in the testing phases, this information can and likely will change before it reaches the live servers.
The Equipment Manager feature was originally slated to be added in Patch 3.1, however Blizzard decided to remove it from the patch due to issue getting it to work properly.
There is no current information on when this feature will be added to the game.
The Equipment Manager feature has two new pieces of functionality. The first is an entire gear set manager (similar to the Outfitter addon). The second is the ability to select certain slots of gear from the character pane itself.
To enable the Equipment Manager, simply enable it under Interface -> Controls from the Main Menu.
Once enabled, there will be a new icon on the character pane window above the Hand Slot. This icon will open up a side window allowing the user to save their current setup of gear.
Once saved, this set can be either be activated from this menu, or dragged down to the action bars and be activated there.
The Single Slot Replacement function of the Equipment Manager is included in this patch as well. What this feature offers is the ability to hold Alt (by default) over an item slot and have a side window open with the items that are available for that slot. This allows for quick and easy access for those one-off pieces that may not be part of any particular set (i.e. Repuatation Tabards, Ammo Types, etc).