Respawning is more immersion breaking than no-respawning. If you get a quest to clear monsters from x area, it doesn't make much sense to do that, get the reward and go back and all the monsters are also back.
1. I do agree that it can be a bit underwhelming to end up with nothing left to kill just as you reach the crux of your power. One way to handle that kind of issue is to have some bonus dungeons which can be repeated.
2. The Divinity series has always had unique loot in the same place every time, and the rest is random. There's no such thing as a particular chest which has a 10% chance to spawn a specific item. I don't see any reason why that would be changed for D:OS.
3. It's impossible to guarantee that every build will be able to handle every situation. From what I hear, the game world should be open enough that you can do other things if you get stuck on a certain enemy.
4. No such thing in Divinity. See 2.
5. I don't understand what you're talking about. Even in games which do have respawning enemies, there's not really a lot of good reasons to revisit areas you've already visited. I guess you're thinking of games like Diablo which have unique monsters that have a chance for better drops, but D:OS is not going to be a loot-fetish game like that one. There's no such thing as Pindleskin runs in the previous Divinity games, and I don't think D:OS is going to start adding them. If that's what you're most interested in, I think you'll be disappointed.
