Source: ROS: Top Four Changes in Diablo 3 Expansion on Legendary Drop and Power Level
1. Paragon Leveling will be approximately six times faster.
The higher Paragon Level you get, the more experience it would need. With the Nephalem Valors go away in ROS, and density nerfed, you may farm for a week without attaining another higher Paragon Level. But good news is that Community Manager Nevalistis has confirmed that you would find ROS Paragon level approximately six times faster.
2. 10 hours without Legendary drops impossible with the Timer system.
Has it ever happen to you that faring for six hours without seeing merely one legendary items? This would never happen again. Diablo 3 would add a timer system to increase your legendary drops if you do not get a legendary after certain time. This would be a rather great news for those who are not lucky in the loot runs.
3. Legendaries from Gambling to be reduced, Legendary drop rates to be doubled.
This is an act to ensure that farming is still the main way to enhance your heroes. The more time you paly, the more chance you can get the legendary items. Not rely on the gambling system and luck.
4. drops