I'm all for this mini.
It's always interesting to see what writers that normally don't do comics can do, and how different is their spin on the characters and stories.
That said, I hope he doesn't turn into the new "main" batman. It has nothing to do with race, its just that for me Bruce is Batman and it's turning kind of repetitive the change of the batman mantle. They already done it with azrael, Dick and Gordon (those are the ones I remember at least). There are endless story arcs you can create without needing to change who is beneath the cowl