Chances are high that Rathbun will NOT reveal anything that makes him legally vulnerable. His sense of self-preservation is too strong and he's made similar claims about past publications that did not deliver as promised. I will admit that this is the first time that he's outlined actual topics with enough specificity however I get the sense that he truly wants to be left alone (not to mention to protect his wife and child) and posted this as a warning shot.
Yes, this is a significant change of tone coming from Rathbun, but he's made many life changes over the last several months. He claims that he's no longer a Scientologist (although he still has considerable ways to go because he still credits LRH with a certain 'genius' that is easily dispelled). Also, having a child most likely changed Marty's focus and/or Miscavige may have made a recent attempt to harm/harass the Rathbuns further.
Regardless of the motivation, it is not likely that we'll see this story become public anytime soon. I can imagine the flood of C&D love notes he received for various firms the very day he published this threat.
Marty is all bark and no bite, sorry to say. His callous actions and treatment of his own victims, not to mention his refusal to address the brevity of his past actions illustrate an arrogant man that cherry picks those he helps while being nasty toward his critics (including those with valid and polite statements). If his past behavior is an indicator of what we can expect, then we can expect more hollow promises, nastiness, and overall disregard for the truth.
I do hope that I'm wrong, but I doubt it.