Hm. I have a hard time separating "discipline" and "motivated" in my mind - they seem like a package deal, though not the same, I know. At least in one direction - to be disciplined is to necessarily be motivated to keep that sort of relationship with something/anything. I guess one could be motivated without being disciplined, but how motivated could you possibly be, then, or why would someone who is motivated without (or with
less; there's the bias) discipline be more motivated, or primarily motivated, more so than the "D" or enough to have that as their letter? I think, for someone interested enough to learn more about what J/P actually mean, the negative connotation that may or may not be associated with it becomes irrelevant, or at the very least, less relevant. To someone who'd rely on that, though, I don't see how that'd even be important, then. That's not to say I'm not in favor of making it as relevant/devoid of negative connotation and ambiguity as possible, however, I just don't see how D/M will accomplish that. By trying to keep them "equal" or neutral, or without negativity (I really think Judging is the perceived negative one, if anything; perceiving seems more neutral, but maybe that's just me, or maybe that's even the point - judging being sort of more "active" and therefore open to either positive or negative interpretation, and perceiving being "neutral" or "passive.") it's like that intent carried over into the meanings of the actual words you chose.
Maybe someone should just make up new words to use.
No negative connotation there, unless it's just displeasing to the ear.
I think the ambiguity is probably the biggest issue, at least for me. Everything I've tried to come up with could be taken too many ways. But I guess that's all you can really hope for in one word, taken from the context of everday use and put into this theory to mean something else/denote something else/or sort of something else but similar. I wish there were just different letter notation used in the context of different theories, in order to make it clearer. If that makes any sense at all.
If any dichotomy carries more negative connotation than any other, I think it'd be the T/F, though, and if the negative connotation is your primary concern (as you said that changing J/P to D/M will only accomplish a reduction in this and not a clarification/reduction in ambiguity) maybe focusing on T/F might be better? But, heh, just because I think that carries the most negative connotation, doesn't mean other people think it does, evidenced, I guess, by your focusing/wanting to change the J/P at all, nor does that mean you haven't thought about T/F too. Argh. ^_^
I gather this doesn't help at all.