The problem with Joyce was not that he was "tight", but that he was very inconsistent. Throughout the whole game, Padres fans in my section were screaming at him for not being consistent. I kept hearing things like "that was a strike two pitches ago." I was thinking the same thing, and this was way before the 8th.
I think your pitch by pitch analysis demonstrates this, as there were some borderline calls he gave to Weathers and some he did not. That has to be frustrating to a pitcher in a tight situation, to not know where the ump's strike zone is.
Regardless, you are 100% about Cordero. That was the highest leverage situation the Reds would be in all game, that is when you use your best pitcher, especially when he is a high K guy.
"Imagination is more important than knowledge." -- Albert Einstein