The Gurubashi Tribe Persists

Originally a 20-player dungeon released in patch 1.7, Zul'Gurub will once again open its gates, featuring updated lore, all-new encounters, achievements, and improved loot! Zul'Gurub is now a level-85 five-player Heroic difficulty dungeon. To provide a new tier above the current Cataclysm dungeons, players can expect to find epic-quality item level 353 loot. The minimum average item level to enter this Heroic dungeon is 346. Those info will be detailed claimed in the new patch 4.1 World of Warcraft.
The Return of Zul'Aman

Ever a player favorite, the level-70 ten-player dungeon of Zul'Aman is being reintroduced as a level-85 Heroic five-player dungeon. Zul'Aman will join Zul'Gurub in a new Dungeon Finder tier of Heroic dungeons, providing epic-quality item level 353 loot. The minimum average item level to enter this Heroic dungeon is also 346. While Zul'Aman will be more of a throwback to the original dungeon featuring many of the same encounters, players can expect to find some updated gameplay mechanics, as well as new environment textures and lighting. Guys who interest in such region will experienced the most adventure in the new patch 4.1.
Class Design

While the WoW official does intend to make fewer balance changes in patch 4.1, players can still expect to find a fair number of updates. Below are just a few we'd like to share with out players right now. Guys, keep in mind these changes don't encompass the entirety of the 4.1 changes, nor do the initial Public Test Realm patch notes.
More To Come