I can relate to a lot of what you wrote. I believe that I have BPD, as I do meet the criteria for it, although nobody has diagnosed me with BPD (I think because of the stigma associated with it). I have also always been sensitive, at least to some things. It would be interesting to find out how many people with BPD tend to be empathic. Whether or not you can find a solid correlation there, I believe that BPD does have a lot to do with not being allowed to be who you are (whoever that is), and the conflict or identity crisis that results. It is a disorder of disturbed relationships also. BPD additionally has dissociative symptoms, and is almost always related to childhood trauma, in my opinion. It is also my experience that people with any kind of dissociative disorders (which I feel are dissociative abilities developed to a point past where they are helpful and actually cause poblems) tend to have high intelligence, resourcefulness, and many abilities. Empathy could be one of those abilities, and may even be related to the ability to dissociate.

Just a few thoughts. You asked an interesting question.