Carolyn Petit wrote in GameSpot's Diablo: Reaper of Souls review from Nfkjasfas's blog

A brand new Adventure mode offered the game an unheard of amount of time, and provided an option for players to keep playing bounties and missions for a long time without having to repeat content from the campaign D2R ladder items. This was crucial since Diablo, unlike its predecessors, allowed you to freely respec your character without having to create new characters with similar class. The level cap was also increased from 60 to. This gave players a greater opportunities to develop their characters to take on challenges at the endgame. 

"Whatever the case may be, Reaper of Souls has it," Carolyn Petit wrote in GameSpot's Diablo: Reaper of Souls review. "This expansion introduces a solid different character, an awesome new campaign, and most significantly, Adventure mode, a devious Blizzard concoction calculated to make Diablo's existing content more rewarding--and more addictive--than it was in the past. "

Reaper of Souls made one additional long-term modification to the formula. although its effects were not immediately apparent when it was first released, it would end up being the main contributor to Diablo's incredible longevity. Seasons was the way to keep players entertained and coming back, offering unique rewards and Legendary gear designed to reward those who were dedicated enough to plumb their depths. 

Seasons would reset every three months and offer special rewards for the most devoted players. In the future, not only can you receive great gear due to an extensive endgame and Torment levels buy diablo II resurrected items, but your equipment itself could be used to tell other players about the exact time and location when you acquired your items.