Story mode has also been axed. It's still there if you want to play it for the first time but for repeated plays most people are gravitating towards the adventure mode. You've got all of the teleports unlocked and there's no cut-scenes, but you can still do all of the boss fights and encounters — in fact, the game is counting on it. Keeping you entertained during Diablo III's adventure mode is a series of bounties that could involve you cleaning monsters out of certain areas, purifying chests, or just giving one of the many bosses in the game a good pasting.
Your reward is loot, because your reward for everything in this game is loot, but also chunks of experience points and cash, followed by a couple of chests full of rare goodies when you finish every bounty in the act. Finishing an entire act can take about 45 minutes, and you can do as many or as few acts as you want depending on how long you've got.
It's refreshing because it's rare to see any RPG working around your timescales - quests in The Witcher don't adjust in length depending on how long you've got, and Final Fantasy VII's save points remain elusive no matter how desperate you are to save and quit.
If you want a larger overarching quest, each season has a 'journey', a series of quests and achievements for you to tackle. Do a lot of these and you'll get series achievements that persist past the end of the season. The objectives are active and shared across all characters, meaning there's a strong meta-game there if you want to go for it. I've found I alternate between being really keen to tick off objectives and preferring to smack a bunch of demons in the face in a quick Rift at lunchtimes.
There are still problems, of course: Most of the classes still play the same way, with little variation - you use your builder attacks to acquire a resource, then you dump out using more powerful attacks. There are some variations in the exact methods you'll use to wreck everything: Wizards turn into Archons to dish out some obscene DPS while empowered, Crusaders are better at taking a hit than giving them out, and Monk's do some stupendous burst damage, but ultimately they all play the exact same way, even if their capabilities are different.
You know what though? That loot treadmill is suddenly much more compelling again, and you'll easily forgive the game its slight flaws after the years it's spent with Blizzard tearing it apart and building it back together as a leaner, more interesting game. Oh, they got rid of that bloody cash auction-house, too.