I think this is spot on. Another point to add is that Dickey had been gaining velocity on his knuckleball year after year and with increased velocity came more strikeouts and better success. I agree the Jays took the risk that they had something very unique and very special on their hands. Given their financial situation, he really was the perfect storm opportunity.
Unfortunately, the velocity dipped 2 MPH in 2013 and he hasn't been the ace they'd hoped for. However, he'd been a very good #3 pitcher at a reasonable cost. Syndergaard and TDA have been absolutely nothing to date - so even though Dickey hasn't turned out as well as AA thought he might, the deal still hasn't been a disaster.
I don't blame AA for taking the risk, just like I don't blame him for taking a risk on Morrow, Santos, Gose, Delabar or Lawrie.