I really hope that was Dick Grayson under the cowl. Not because I want him to die, but because it makes sense. From Damian's age, the name of his journal, and frankly, Bruce's appearance at the end. It doesn't work with Talia's description of his conception, but ew.
Things I liked: Damian grew on me. I was disappointed when they killed. If any character can come back from the dead though, it's the grandson of Ra's al'Ghul.
Things I didn't like: Kubert seemed to have trouble with the character. His pattern went from pretentious (what I expect) to sulky teen (unexpected). A consistent tone would have worked better.