Dear Ayya @vimala , thank you for the extensive research and the article, this is very interesting and helpful information!
However I would like to disagree on some of the conclusions and on Bhante @Brahmali’s current choice of translation.
The major inconsistency I see is that, as far as I understand, you take the premise that the word paṇḍaka, and thus the rules concerning it, were not from the Buddha’s time but were added later – but then choose to translate it with the meaning it supposedly had at the Buddha’s time, and not at the time when the rules concerning paṇḍaka were actually laid down.
I see that as problematic because it translates a word used in a specific context outside of it’s actual context, which renders it again incompatible with the precise context in the vinaya.
So for example, Ayya @vimala, you showed with regard to the Jain references, that they suggest the word paṇḍaka or napuṃsaka to describe people who are sexually non-conform – psychologically and/or biologically – and who display/act out excessive libido, or at least are perceived/prejudiced in such a way by popular culture. - Without the need to define a time for when the vinaya piṭaka was laid down, this is exactly the context in which we see the word paṇḍaka used in the vinaya (and suttas). For example, the origin story to why paṇḍakas are excluded from ordination (Kd 1.61.1) tells about a paṇḍaka who went around in the monastery and asked monks to “commit an offence with [him]”. To see this paṇḍaka simply as a eunuch doesn’t seem very reasonable, it is obviously his specific outward sexual desires and how they create trouble for other monks (and for himself as a celibate monk) that are the problem, not whether he has or hasn’t got testicles. In the story he goes to different groups after being turned down repeatedly in a rather unfriendly way and only a group of low caste monks finally consented to his request, suggesting that paṇḍakas were seen as impure and higher caste people didn’t want to have to do with them. When the matter becomes public, people criticize it in the following way:
“These recluses, sons of the Sakyans, are [paṇḍakas], and those of them who are not [paṇḍakas], they too commit offences with [paṇḍakas]. Thus they are one and all unchaste.” (transl. by I.B. Horner)
-> again, the main problem with the paṇḍaka is that he is sexually unrestrained and abnormal and that there is a social stigma seeing paṇḍakas as having such characteristics and as being impure for those reasons.
As far as public opinion goes, AN 5.102 states:
“Mendicants, even if a monk is of impeccable character, he might be suspected and distrusted as a ‘bad monk’ for five reasons.
What five? It’s when a monk frequently collects alms from prostitutes, widows, voluptuous girls, [paṇḍakas], or nuns.” (transl. by Ven. Sujato, he chose ‘eunuchs’)
→ if we assume paṇḍaka should fit into this list, then all five of these are popularly seen as possibly more willing or more likely to get intimate with a monk than, say, a married woman. And so it is again not reasonable to translate paṇḍaka as eunuch here, because why would a eunuch be seen as having a high libido? I think rather to the contrary!
I believe with the above, the problems concerning admission of paṇḍaka into the order have been shown, and I think that it is fairly obvious in the face of all the evidence from the theravāda vinaya as well as from the Jain and Vedic references provided by Ayya @Vimala, that the term paṇḍaka in the vinaya refers to males who are sexually non-conform and unrestrained in that. That is more precisely: excessively effeminate non-cis biological males of the unrestrained type. (of course, the commentaries go into more types of paṇḍaka that are not precisely covered by this, but as far as I understood you didn’t want to go into the commentarial exegesis of paṇḍaka, right?).
The itthipaṇḍaka would then be fairly easy to define, and would also actually make sense and be reasonable in the face of the rules: an excessively masculine non-cis biological female, in her sexual behaviour/signals unrestrained.
I don’t see how one could reasonably advocate for the inclusion of so-defined people into the saṅgha, since a rule to the extent of not granting them admission fulfils all the possible reasons the Buddha mentioned for the laying down of a rule.
Public opinion and the protection of monks, or their celibacy (and as a result of course the long-lasting of the sāsana) might be the main points.
Since social attitudes towards LGBQT people are still far from being neutral or positive, whether in the West or the East, whether in the cities or (especially) in the counrtyside of both West and East, I believe that this rule is still contemporary, in regard to the problematic aspect of social stigma and popular prejudices or suspicions.
(But let me make one thing clear at this point, in case it hasn’t been: As far as I understand and tried to define paṇḍaka, it would not include homo- or bi- or queer who are not outwardly obviously gay, etc… it is a question of acting out vs. controlling lust in general, not of who lust is directed towards)
As for the problem within the saṅgha, it is also just as contemporary. Ayya Vimala suggested that if paṇḍaka were characterized by excessive libidinousness, it would also have to be linked to cis-gendered people, but I don’t quite agree: the situation for cis-gender people is significantly different in the saṅgha: horny males will just be around males, whereas a horny paṇḍaka will be living closely (as close as arms-reach, at least fortnightly) with his object of desire → a more fuelling and more dangerous situation!
For a conclusion of this comment let me come back to the beginning of my response: If we assume that paṇḍaka were inserted into the vinaya at a later time, we should translate it in accordance with the meaning it had at that time. And the vinaya itself does quite clearly state the context in which it uses the term paṇḍaka. If we don’t like a rule, that is fine. But we should for that reason not change the content of the Theravāda vinaya!
Let’s take for example hermaphrodites: they aren’t included under paṇḍaka, because they have their own separate rule that excludes them from ordination and expells them if they are already ordained. One might think that it is unfair and sad to exclude them from the possibility of ordaining in the saṅgha - and I would totally agree – but we won’t for that reason rewrite that rule in the vinaya piṭaka according to our feelings or in accordance with what seems fair in a particular culture at a particular time, would we?!
After all the Theravāda vinaya is what it is: it’s the vinaya of the Theravāda school and as far as I understand we all agree that it does not precisely correspond with the vinaya that was practiced during the Buddha’s lifetime and that was laid down by him.
Nobody is forced to identify with Thervāda, and so we can still live with faith in the Buddha and in what we understand as vinaya , regardless of what is written in the theravāda vinaya piṭaka.
And if we don’t like Theravāda opinions, we can always propagate our own opinions, without needing to change theravāda for that matter, but that’s just my opinion… 
Thank you for bearing with my long comment and I would appreciate your replies 
oh and I almost forgot: Venerable @Brahmali my concrete suggestion for your translation would be to use something like the combination of the two options you had before:
"licentious sexual non-conformist" ?!?
(Also I miss you and hope you’re doing well.)
