There are a few problems with releasing only the xml's. The first being how the modders would test any fixes they find and how would the modders test any changes they have to make to adjust the xml's to their mod?
I know there's general leg-work that can be done by some modders but it would seem the difficulties outweigh the benefits.
If the xml's are released publicly the potential for misunderstanding and unnecessary -gates rises exponentially. Let's save the torches and pitchforks for when we actually need them