1. Thats the idea. They are adding in cutscenes, so if there is like a Treasure Goblin behind you during it, you might see it close enough for seeing the details. All monsters get personal details.
2. Making monsters more aggressive during night is something for a minor quest or a feature within limited area. Very cool idea. I dont see this on a general note, which would result in casual players only play at daytime and waiting in town for night to be over, and veteran players vice versa.
3. It seems like Nephalems are rare, and the first born ones was / is more powerful than the watered-down Nephalems that got passed down the generations. Today the titans (the nephalems) are humans, the end-result in Sanctuary mostly have less powerful beings.