I think an excellent example of good camera functions would be the NWN games. That camera functions very well and is similar in style to Divinity Original Sin.
I do however like being able to move the camera with wasd, using the mouse at the edge of the screen is a little clunky right now and requires a couple retries (especially on the right side of the screen) to get working properly.
The camera in NWN is exactly what I had in mind. In my humble opinion it's still the best D&D game made and I think that a lot can be taken from it even all these years later.
