That could be a nice moment. But after that, what would DC or Devin Grayson possibly do for the next issue? Nothing in serial fiction makes sense if we neglect the fact that the most important thing is to sell the next installment. And if that means ignoring (or, more often, finding a less than fully convincing writearound for) an obvious solution, then that's what the storytellers do.
One way the company could have kept up Blockbuster's threat and acknowledged Nightwing's place in its hero pantheon is for the big guy to use his knowledge of Dick Grayson's identity to ferret out the identities of lots of other heroes--up to and including Superman. But that would have required all of DC to bend around a story in Blüdhaven. And it would have brought on a whole new level of obvious solutions to avoid.