This means you have a month and a half to get a group together and kill these encounters on heroic for a guaranteed drop. Please note that, according to Draztal, this change will occur on the release of Mists itself, Sept. 25, and not with the pre-release patch 5.0.4 that comes out this month. So even after the talent systems change, you'll still have some time to farm for your mount. Get cracking.
It's open warfare between Alliance and Horde in Mists of Pandaria, World of Warcraft's next expansion. Jump into five new levels with new talents and class mechanics, try the new monk class, and create a pandaren character to ally with either Horde or Alliance. Look for expansion basics in our Mists FAQ, or dig into our spring press event coverage for more details!