Patch 6.2.3, which could very well be the final patch before 7.0 (though I wouldn't be surprised to find another one for Mists of Pandaria timewalkers) will be arriving next week.
Probably the biggest feature of this mini-patch is the introduction of Cataclysm timewalker dungeons. These will be:
Lost City of the Tol'vir
The Vortex Pinnacle
Throne of the Tides
You'll note, of course, that this is six dungeons, with one of them being a post-launch dungeon. Guess what? BC and Wrath timewalkers will get similar additions. Burning Crusade timewalking will now also include Magister's Terrace, while Wrath will get Pit of Saron.
Additionally, and this is maybe the most exciting thing, is that a new mount, the Infinite Timereaver, will be a random drop from enemies in any timewalker dungeons.
There will also be a vendor at the Earthshrines (the Cataclysm portal areas in Stormwind and Orgrimmar) who will sell new toys and other Timewarped Badge rewards when the event is on.
The first Cataclysm timewalker event will start the day after the patch, this coming Wednesday.
Other features include:
The Return of Valor Points and Item Upgrades:
Valor points will now be awarded for completing the first random heroic dungeon per day, completing Mythic dungeons, doing weekly bonus event quests (except for the pet battle one) and completing a raid finder wing (the first wing you do each week - don't feel you need to run them all.)
Here's hoping there will be actual gear rewards for this in Legion, but for now, you'll be able to upgrade your gear by 5 item levels, twice per item, 250 VP per upgrade.
Improved Item Rewards:
Mythic Dungeon loot now has a chance to have anywhere from 685 to 725 item level (in increments of 5,) with higher item levels being rarer. Bosses in mythic dungeons also have a chance to drop an heirloom trinket that will scale up to 110.
Additonally, baleful gear also has a chance to have an item level from 655 to 695, also rarer the higher the item level. (I believe that you'll just not use Empowered Apexis Crystals on pieces that hit 695 on their own.)
Warlords Season 3 starts off.
New PvP season, with the top-level gear scaling up to 740 in PvP
...And a bunch of balance changes!
Hopefully this stuff should tide us over until the Legion beta begins, which I hope is soon!