In a nutshell, loot, and lots of it. More specifically, significantly increased drop rates are the order of the day. Now, we've heard the jokes as well. "Significant" means an increase from .01 to .02 percent, right? Wrong, as this time NCsoft means business. Aion's devs have offered up some specific statistics via press release, and you'll want to check out the tables after the cut for all the details.
If you've spent much time in the lands of Atreia, you're probably familiar with Beshmundir's Temple and the named bosses contained therein that players often farm for loot. Over a period of 20 Perilous Path Temple runs, testers collected 138 total loot items. Of these, 121 were fabled quality (including wings), and 17 were eternal. Similarly, NCsoft testers cataloged 20 runs through the famed Dark Poeta dungeon, recording all loot items acquired from Spiritmaster Atmach to Brigade General Anuhart. A total of 68 fabled items dropped, which averages out to 3.4 per run. This was also sans the final boss, so the actual numbers will likely be higher.
Finally, NCsoft is also gifting players with the new Aion Adventure Guide. According to the press release, the guide will "give players advice on where to find level-appropriate in-game content that will help with progression and reward them with items along the way. Crafted in-game messages and guides let players know where to go to find game content (quests, instances) that help progress them to the next level and give them hints on how to use new areas, such as the Abyss, and systems, such as Stigma Stones to their advantage."
Don't forget to fly past the cut for a detailed breakdown of the Beshmundir Temple runs in table format.