Having read through the other posts, and the comments on the original post, there were some poor deals the Jays have pulled off. There are times when the players or managers force your hand (Green, Halladay, Olerud) when you are almost going to get destroyed.
Picking up Mike Sirotka and his bad shoulder has to go near the top. Giving up any asset for a guy who never pitched has to be high up on the list. Signing one to an extension first makes it more painful. Considering he was a guy with an increasing BB/9, declining IP numbers and didn't miss many bats, it was poor all around.
The Dickey deal is another one that is painful, though for different reasons. Dickey did provide some value, and there were two playoff runs in his tenure, but it was ugly from the get go when Syndergaard was included. Considering Noah already has more WAR than Dickey provided during his entire tenure, this one could hurt for a long time. I can't help but imagine a rotation of Syndergaard, Sanchez & Stroman, supported by Estrada and Happ, the Jays could contend for the playoffs without much of an offence.
Hendriks for Chavez is one of those deals that makes very little sense, but at the end of the day, I don't believe it's going to change much one way or the other. Chavez is already gone, hopefully for the last time, and Hendriks is going to be a solid reliever, but those are a dime a dozen.
The other one that jumped out at me was trading Denis Boucher, Glenallen Hill & Mark Whiten for Tom Candiotti & Turner Ward. For 16 decent starts from the Candy Man and 245 PA's of 77 OPS+ from Ward, the Jays gave up 2 solid young OFers in Hill & Whiten. Both had already put up the same offensive output for the Jays that Ward would put up, and lost on the future returns. Although the deal didn't have much of an impact in the long haul (Whiten was blocked in RF by some guy named Joe Carter & Hill was blocked in LF by Candy Maldonado), it still seems like a horrible deal for the Jays.