Hmm this is a tough one.
I’m clearly in no place to discuss objectively, because my understanding of Nibbana is closer to eternalist bias than anihilationist, even thou I’m not eternalist absolutely! (pun intended). At least I think so. 
I understand difference between “eternal bliss” and Nibbana. Eternal bliss suggest existence and experience of time, while Nibbana is beyond such categories.
There is a danger of course that poeple will mistake some rupa-loka or jhanic experiences with Nibbana (from pragmatic perspective thats the reason why we are warned about eternalist danger, I suppose). But I think when people get right teaching, they will understand the difference. And the texts explain that difference clearly. And this differences don’t point to anihilationism, but to inexpressible nature of Nibbana, except of claiming that it is “highest happiness” (Ajahn Brahm also writes about it).
We cannot say that after/“in” Nibbana there is “nothing” either. Thing is we cannot say anything about it strictly if we are honest. We can only point to it, and so did the Buddha.
Is it interesting that you wrote that Buddha chose the word “Nibbana” with straightforward meaning. I must say I very deeply respect you and your work and wisdom Venerable Sir, and that I take to heart your interpretation and I will remember it. I still will share my own intuitions for consideration and discussion.
From my perspective, I cannot say if your words are interpretation or facts, because my scope of knowing pali makes me unable to make such claims. Also I havent realized Nibbana yet, so I cannot speak from experience either.
But my feeling and interpretation so far is such, that Buddha used term Nibbana in somehow poetic and metaphorical way… and that he did that on purpose, because no word could express it straightforwardly anyway!
It is importaint to note that of course, Nibbana means “extinguishment of a flame”, but it doesn’t say what exactly happens with the “flame” afterwards. It is all very vague and mystical. I don’t see anything wrong with the fact that there is something mystical about term regarding ultimate reality. I also don’t regard mysticism as something inherently wrong.
I understand that you want to translate everything and it is very reasonable attitude, but personally I take Nibbana more like a “specific name” pointing towards inexpressible, rather then term defining something in particular that can be grasped through intelect, so, there are two options:
- You could not translate it because it is metaphorical “proper name” that is not to be translated, like names of poeple.
- Even if you don’t consider it a “proper name”, but a regular word that should be translated, you could still make this one exception, due to very specific and unique characteristic of Nibbana (transcending samsara, so cannot be expressed in words of samsara anyway). If it cannot be explained, why translate the word that points to its inexpressible nature anyway?
Thats why I personally believe that this term should not be translated, but of course it is only my suggestion.
I feel the texts are deliberately flirting with this nexus; that is to say, the Buddha deliberately chose a term that leans to the side of annihilation rather than eternalism. If we leave it untranslated, I think the emphasis of the term flips the other way: most people would read “Nibbana” as “an eternal state of bliss”.
It is exactly the same situation the other way around, even more. Translation suggesting interpretation.
I’ve had once situation when I was playing meditative gong concert and was speaking during the concert some meditative instructions for beginners. After the concert, one Lady criticised me that speaking the instructions that was disturbing her listenning to the gong. I’ve said that I just wanted to help, and she said that I lack faith in my listeners, and that I should trust them to handle the experience. And she was right and I no longer speak during the concerts, I leave it all to music and people and I trust that they will not fall asleep 
(not always working, but still it works better than before 
)
I think it could be the same situation. Shouldn’t we trust that people will understand Nibbana correctly when reading the texts? I think it is better than suggesting towards annihilation, but thats just me Maybe it’s just my ego defending itself from vision of extinguishment?
PS: I also feel that leaving the term untranslated motivates the reader in a wholesome way. Truth is, we can read actually anything in “Nibbana” and the metaphor of flame going away. We can think it is gone, we can think it become “one with the air” etc., but then we know we actually don’t know. It works like a koan. The more you try to “get the meaning” of Nibbana, the more you know you just can’t. And you understand that in order to get the meaning, you have to meditate, practice noble eightfold path and then you could experience Nibbana and only then you will know what it is/isn’t. But then, you’ve “finished the task” and this is what Buddha Dhamma is all about.
I can see that this translation is conductive to spiritual progress aswell 