My take on it is that the general consensus among talent evaluators is that Pomeranz "broke through" when he added the cutter, and they're gushing about his makeup and fire because he basically talked his way into being considered for a rotation spot. This is a big gamble for both sides because of the volatility of prospects and Pomeranz' track record, but as I've said before, DD is rarely wrong in these types of trades.
On the other hand, I am willing to bet that the Padres asked for Kopech and the Sox balked, as I said before.