Diablo has a completely differnt design philosophy with respawning enemies. Also Diablo 3 is an always-online game with your characters stored online on the servers. That's the worst abomination of DRM ever made. Most of the people here hate this kind of stuff and Larian would never even dare to come up with an always-online concept...
And no, this game is NO turn-based Diablo 3. Not at all.
This game is designed as a story/quest-driven RPG not as a leveling/loot driven RPG. If you want to play in co-op then you should play the whole campaign in co-op. It's not a game which you play for 20 minutes to kill some pointless genereic enemies and loot some gold. It's a game in which you do quests. Everything in this game is based on quests and story and not on pointless enemy-clicking like in Diablo. Maybe you should inform yourself better about the basic principles of game design and different design approaches...
