That's how I see it too. The Reds did not want Dunn back. The signs were clear as day.
This trade avoids the unpleasantry of risking offering Dunn arb (He might've accepted, as some FAs have done, like Maddux at Altanta).
IMO, this A ball pitcher and two PTBL might be better than 2 comp picks anyway. Let's wait and see. As someone else pointed out, the AZ prospects are already paid for and further advanced.