Blizzard today rolled out World of Warcraft patch 5.0.4 featuring an extensive revision of the talent tree and glyph systems, account-wide achievements, pets and mounts and several quality of life improvements including AoE looting and Battle Tag integration.
If you were looking for new Mists of Pandaria content to become available, you might have been disappointed after logging in after the massive patch. The new Monk class and the Pandaren race are not yet available in game. With the exception of a few dungeons reworks, Patch 5.0.4 is not intended to unlock Mists of Pandaria content, but bring World of Warcraft up to speed with new systems and features to be implemented with the release of Mists of Pandaria. Patch 5.0.4 is a soft start to MOP.
Patch 5.0.4 does feature a massive overhaul of class talent system. No longer do players receive a talent point every other level, but unlock a talent tier every 15 levels. Each talent tier offers three options of which only one can be selected. Talent tier sections can be altered as you go and do no longer require a full reset at the class trainer.
While some may argue patch 5.0.4 limits player customization, it adds a wealth of new quality-of-life improvements. Achievements, mounts and pets are now account-wide. AOE looting and cross-server zones have been implemented. Battle Tag functionality has been extended. Additionally, several improvements to the UI, including the Spellbook, made it into the patch.