The upcoming patch 5.0.4 only contains part of Mists of Pandaria's content, but it does bring all of its class changes. Our new talent trees and glyphs will be in place, and our specializations will be dramatically revamped. While rogues are receiving fewer changes than any other class, we will experience a shift.
Our new mechanics will be in place following patch 5.0.4's release on Aug. 28. We will have nearly a month to learn our rotations before Mists' official launch. That should be plenty of time to get our gear and glyphs in order in preparation for leveling in Pandaria. Poisons and talents will be at the forefront of our effort to adjust.