The amount of experience required to level between 60 and 70 has been reduced.
Approximately 30% less XP required to level (60-61 used to require 500,000, now 290,000)
Quest XP increased by approximately 30% (Quests at level 64 still gives the standard 10400 XP, so this needs confirmation).
XP gained by kills did not change
Mana and Energy no longer use the "tick" system and instead climb up in real time.
HP still tick.
The Azeroth World Map has been updated and now shows the Continent of Northrend.
Most other slider video settings have higher maximums
8x anti-aliasing is now an option in the video settings
Shadow setting in the Video settings page/tab.
Headphone sound setup in the Sound settings page/tab.
As of now the titles "Champion of the Naaru" and "Hand of A'dal" are no longer attainable. You can still complete the relevant quests but they will not award said titles. However, some people are still able to gain these titles so long as they are not level 71. According to petitions filed, players that still held the quests near the end of the chain were able to complete them and gain the title.
The interface, video, and sound options panels are reworked to be better organized.
Video and Sound options are accessible before you log in now.
Down ranking a spell is no longer beneficial. In most cases, downranking costs more mana than the highest rank.
Total disk space required for the World of Warcraft folder has been reduced. The DATA folder for a Burning Crusade install now uses 7.66GB instead of 9.14GB in 2.43.
Numerous graphics for Northrend characters are present in the PATCH.MPQ file. This may be to patch content on expansion release, or to speed up installation.
Jumping while underwater no longer works. Instead, you start to swim upwards when holding space. Even if you are swimming straight ahead, holding space will force you to the surface; it basically has the same mechanics as a flying mount.
Non-Forsaken characters can now hold their breath longer, changed from 60 seconds to 3 minutes. Forsaken still benefit from Underwater Breathing, which has been reduced to a 233% benefit. Consequently, regaining your breath from a fully depleted bar also takes three times longer from what it used to be.
The auction house now has a Glyphs section with subcategories for each Class.
The auction house now has a Container subcategory of 'Inscription Bag'.
Players will no longer receive mail with an hour cooldown when they sell an item in the auction house. Instead, this information will be displayed on the player's Auctions tab in the auction house window until the timer runs down and the money is delivered.
The Currency Tab is currently filled by all Marks of Honor and all Badges as well as Honor/Arena point listings. Other reward tokens are not included (i.e. [Halaa Battle Token], etc). Also, the Marks and Badges can only be found in this tab, giving up more space in your inventory.
Ship crews (last seen for a short while after the launch of Patch 2.3.0) have returned! Ships and zeppelins now enjoy a full selection of crews, some of which even sell reagents, food, or repair items. Some boats now sway again as they did in Patch 2.3.0.
The Sylvanas Windrunner model has been updated from Undead Night Elf to Undead High Elf, including clothes, armor, and now carries a dark colored high elven battle bow.
The Varimathras model has been redone. Armor, wings, color, and face, and horns have all been adjusted.
Although the official patch notes state that only newly tamed low level pets are levelled to within 5 levels of the hunter, this instant levelling also applies to any active pet more than 5 levels below the hunter.
Miners now receive the passive ability Toughness which adds HP based off of the skill level. (Rank 4 gives 100 hp. It could be 25 hp per skilltraining. 25 for Expert, 25 for Master and so on. Your mining skill level seems to be the "ranks")