There are by default "way more quests" than Diablo II ever had, including in variety. All over the game world there are "random elements" to discover and loot.
It's not just the quests and dungeons that'll be randomising but of course the gear we scavenge too, but the enemies we face will be switching their power sets as well. Let's not forget the rune system Blizzard is bringing to Diablo III expanding customisation.
"So the fact that we have random dungeons, random monsters, random loops, pretty much random everything. Every time you go around a corner in a dungeon, you don’t know if you’re going to see a brand new quest that you’ve never seen before," teased Martens.
"You might see the same monster, but with totally new powers. You might see a totally different monster,” he added. "We’ve added way more quests, more variety of quests. We’ve randomized the quests, and have these sort of quests that are self contained."
"For example, if you enter a dungeon in Diablo III, there might be somebody standing at the entrance, like a treasure hunter, saying, “Hey, I heard stories about the Idol of Rygnar is hidden somewhere in this dungeon. Help me find it and you can share in the reward.” Then you go through the dungeon and protect this guy."
"Then you’ll find the idol and you’ll get the reward. People will turn on you…you’re never quite sure what is going to happen. We’re adding all those random elements all over the world. There is way more quest content overall than Diablo 2, period." Great to know!
"That aspect of it is one of the things that Diablo is most well-known for, and I think that we do that better than anyone. I think that’s the feather in our cap.”
Runes will have quite a profound effect on our character's skill tree. Martens gives an example of just how different you can make an ability.
"You can take a witchdoctor power called “Plague of Toads“, and turn you into a giant toad. It literally swallows the enemy and spits out the gold inside of them and so on. So the customization is extraordinarily huge. It’s astonishingly re-playable,” he said.
the full interview between AtomicGamer and Kevin Martens.