Love it! I will definitely be sharing this little flowchart. Anyone called to jury duty needs to be familiar with it, along with the play "Twelve Angry Men."
It is said that "trials are too important for juries." It's also been said that "a jury consists of twelve persons whose job it is to determine who has the better lawyer." I think anyone with a functioning pair of eyeballs knows that the jury box has been no place for a well-informed citizen for quite some time now.
That being said, I do have a bit of a problem with your assessment of negligence being subjective. I think there are indeed objective standards by which negligence can be measured, such as the lack of a reasonable expectation of a time traveller materialising on your shooting range. "Reasonable expectation" goes right along with "reasonable doubt" in the context of acquittal - which you could argue is subjective, but I would counter that any plausible alternative is cause for reasonable doubt, and it can be determined objectively. Just a little quibble I have, otherwise, I agreed with everything you said.