BlizzCon 2013 introduced a new game mode to players – Adventure Mode, and it has soon attracted most of the players' attention. Some people even doubt that if there are players to explore campaign mode when the new mode is available. Let's see the answer from community manager.
As we all know, there will be a dungeon in which everything is completely random. You don't know what you will meet or where you'll go in the dungeon. The mystery is the most attractive part of adventure mode. And of course people want to farm and fight at a unknown place, cause the result may be few players choose to challenge campaign mode at the very first in the near future. But after a period of time, you may want to make a change and return to campaign to enjoy linear path. That depends on your requirement and interest.
Adventure mode is more rewarding than campaign mode and there used to have complaints about this. Now it's no longer a problem because the acts in adventure mode will be unlocked in turn as you play campaign mode. Whether you are a casual gamer or not does not matter now. like the post shows.
You can choose any act to explore in adventure mode, and the monster level will change with you. More details about this, as usual, is unknown. The system is still under modification and improvement, according to community manager.