There is no depth to Bruce Wayne, because as you yourself have noted, Bruce Wayne is a mask. He's the 'secret identity' Batman is the the actual 'person' here.

Mind you, this is coming from someone who LIKES the idea of Afleck playing the role. I actually think he can pull it off and I'm excited to see what they do w/it.

But saying Bruce is the 'hard part' is absurd. Bruce is a cariacature. Just like Clark Kent is Superman's critique on humanity, Bruce is Batman's critique on the failing of the elite.

It's not a complete person tho, not by a long shot.