This fascination that you have with letting pitchers "work it out" is quickly demonstrating why ex-pitchers should not be managers. I have not seen such shoddy bullpen management since Bob Brenly stumbled his way through the 2001 playoffs with the best team in baseball at the time. I get the sense that you are managing the bullpen on "feel" and "gut", which is commendable. You are your own person and not a mindless automaton. Nor are you a puppet whose strings are pulled and twisted by a shadowy figure, one hand on the popsicle sticks and the other hand furiously typing away at a spreadsheet. You have proven to be thoughtful and methodical, which are traits needed to manage the course of six or seven months and 162 games.
On the other hand, there is something to be said for the ability to take action when action is needed. There was no shortage in sources of information that painted the picture that Thatcher was not effective, not the least of which should have been the climbing values of the wooden integers in the outfield wall, underneath the giant "R", coinciding with the tally of runs for the opposite team.
Given the situation, pulling Thatcher well before the fourth run was scored against should not have been seen as an indication that you were losing faith in him. Rather, it should have made the message perfectly clear that you actually have lost faith in him and for the rest of the bullpen for that matter. I have no faith that any member of the bullpen will succeed and that is your fault for leaving them in to fail.
It is not over by a long shot. The lead that the Diamondbacks have built is not insurmountable, but the first month has not been kind to the Padres and you have not been effective as a manager.