Blizzard has announced a new major content patch for Diablo III: Reaper of Souls aimed at improving replayability.
The first big change to come along wtih patch 2.1.0 is the addition of Seasons. Players will be able to start with a level 1 character and work toward unique Legendary Items and Season-exclusive rewards.
Seasons will also feature Conquests which are special Season-only achievements that will challenge the player to take on a variety of different playstyles to keep gameplay fresh. Each season will bring 10-15 Conquests, and the first 1000 people to complete a Conquest will have their names placed on said Conquest's leaderboard.
The next large additions are Greater Rifts. Greater Rifts are a unique type of Nephalem Rift that are designed to be more challenging and provide better rewards upon completion. To access Greater Rifts, you'll need a Greater Rift Key, which you can obtain by defeating normal Rift Guardians. Some of the challenges in Greater Rifts include a timer to race against by filling a progress bar with each monster kill, the removal of the ability to resurrect your corpse or respawn in town and the removal of the ability to teleport to a party member with their banner. Upon completion, you'll advance to the next difficulty level.
Finally, the patch will bring a new area to the game - The Cesspools. The Cesspools were originally supposed to be in Act 5 as the sewers of Westmarch, but the map wasn't complete by the time Diablo III launched. When you install patch 2.1.0, you'll notice The Cesspools popping up within Nephalem Rifts and Greater Rifts.