We're basically on the same page and I agree that there are a lot of questions worth considering; as someone that was rather dismissive of aaronsw's course of action in the first place, I've certainly been thinking about how I expressed those views, even though my views have not changed much since.
The only thing I'd add for consideration here is that it's not really the prosecution's job to worry about a defendant's mental state; as I understand it, it's up to the defense team to bring that sort of issue to the attention of the court (ie the judge). Not to do so, but then to bring the matter up in negotiation, looks an awful lot like an attempt at manipulation instead of a sincere concern. The whole idea of the court as a neutral finder-of-fact is to provide defendants with an unbiased ear for such issues so that they're not dependent on the good will of prosecutors.
Yeah. Just to be clear, I don't think prosecutors should have to wring their hands and back away from plea bargaining every time any defendant claims emotional distress. I do think there should be a framework for evaluating claims of defendants being at risk for self-harm and then selecting appropriate courses of action; in Aaron's case I think that prior evidence (e.g. content from his blog) as well as the nature of his crime should have been suitable grounds for an adjusted plea bargain under this hypothetical framework.
Courts are messy affairs; there's still a lot we don't know, like the disposition of the judge, so I can accept that the defense should have brought that to the court, but would rebut that we don't know that they didn't, or that they weren't able to for some reason. Either way, I don't think that completely exonerates the prosecutor's office in this case.