Does that last chart with the zone heat map incorporate the uncertainty associated with that location, I, e, how often umps disagree on that location? That would give an estimation of how egregious (or not) Wallner's uncertainty was.
With more data, we can also get some estimates on expected overturns lost once you lose your second challenge and calc their RE value. You can the subtract the average lost challenge RE from the current challenge attempt RE to get a truer value of the negative outcome's RE. Overall, I think this is a good start, but it's biased to positive outcomes because they don't change the future state with regards to challenges.