As I said in another thread, I can't blame Dombrowski for the underperformances of the players. IMO, he overpaid for Price, Kimbrel, and Pomeranz, but acquiring an 'ace', a closer, and a solid middle rotation pitcher were all necessary. All 3 of those guys should have been upgrades.
Were there other routes that Dombrowski could have taken instead of the ones he chose? Probably, but we don't know what those other routes were and how much they would have cost. At this point, it's all speculation and second guessing.
All that said, I really think that Cherington should have been given more time to see his vision come to fruition.