I think it may not be too "mysterious".

I agree on Aviendha's vision being invalid at this point (see my other post for the full rationale, but it's similar to yours). I agree that Aviendha's vision is divorced from the prophecies and not their real fulfillment. We know this, know the remnant isn't in sight in this and Rand isn't breaking the Aiel like dry twigs, or with the Leaf as in the KC verse.

It's obvious Aviendha will want to do something. It's long been the mission of the WO to puzzle out how Rand will destroy/break and from there try to make the remnant as big as possible (the WO don't believe in fighting against the inevitable. Their philosophy is to accept what you can't change and put your efforts on what you can change.) So basically, Aviendha just became the key Wise One as far as their mission is concerned, and that's about to be completed by reaching the powerful status Sevanna dreamed of: the wife and Wise One of the Chief of chiefs. Aviendah may not have special status, but her power will be real.

When Rand let the truth out about but a few details of the life of the da'shain, the Aiel were shaken and a percentage just fled (notably to the Tuatha'an who were in the Waste to ask to be taken in - some have forgotten there are now ex Aiel warriors with some of the Tinker groups).

Now it's much worse, the topic of debate could be that all the Aiel should join what they refer to as "the bleakness". All first hand knowledge of the da'shain philosophy, purpose, talents etc. would forcibly have to come from Rand/LTT himself. The whole notion that the Aiel should now abandon their warrior culture if they want to survive would shatter the Aiel. What do Aiel do when they are faced with inevitable doom? They find an honorable way to commit suicide. Cornered Aiel in battle try to die heroically, male channellers go uselessly to SG to die (and don't tell them dying but with honour is useless.. they don't see it as useless at all), the crippled warriors go to the desert to die etc. Then there is this central belief of the warriors that atonement for their Sin will come by fighting the Shadow at TG (which we know isn't the sin, the sin was abandonning the Way of the Leaf... "find safety, survive and don't abandon the Way" was the wishes of Deirdre's group. Giving them dangerous OP objects to hide was by and large a device to convince them to abandon Paraan Disen as Da'shain didn't want to leave). It's not a coincidence at all that the Aiel refuse to use the name Last Battle either, dismiss it as "Wetlands prophecies" (it's mostly the WO doing this, - the Aiel themselves don't seem to know the KC much) when we know it's not at all that they don't believe it will happen, it's merely the names Dragon/Last Battle (TG) they refuse (their own name is meaningful and even more dire... the Last Day). There is no "last battle" in traditional Aiel views - your last battle is the one you die at. The trip in the Glass Columns gives a hint to every WO/clan chief that there actually could be an Aiel "last battle". They know that following visions of the future, the Rhuidean AS insisted for the Aiel to always be lead by those who can know and accept who they once were, or they would die. And the Aiel leaders then agreed to this, on a water oath. The WO/cc have long been in denial. They know there's a reason why the Rhuidean AS wanted the leaders to know their past. They choose to focus on the compact in Rhuidean, on agreeing on the way to choose chiefs and WO and forget the rest (it appears the Rings of the WO may have screened candidates for the one with the right future who would be shown the futuristic vision by the Glass Columns. Several WO must have seen glimpses of post TG/TG times from their trip in the Rings - they just don't tell, but after Aviendha tells them what happened to her, they likely will) The Wy must suspect what they once were is a key to the Rhuidean prophecies and the final fate of the Aiel, they just skirt around it, just like they are quite ill at ease (and stubborn) whenever the prophecy that says they might return to serving the AS is brought up (the most pragmatic said stuff like "it may well be, but that's not here nor now, so let's change the subject". Aviendha brings back a key piece of the final puzzle: if the Aiel remain warriors, they are doomed to a slow complete exctinction whithin a few generations, them and the Aes Sedai and many others.

Aviendha won't sit idly and all her storyline was concerned with the struggle to give up being a warrior (all that remain for her personally is to show the way and give up using the OP for violence...a return to the WO's traditional ways. Many WO went through that (not nearly all of them were FDM), but for Aviendha the process is really fresh.

Since TSR, the Wise Ones have seemingly tried to avoid/delay coming to that (but we don't know if they didn't have dreams about Aviendha's real role they chose not to tell her because it would have broken her... they may be less in denial than we think, merely waiting for the inevitable time to come to face that), but it appears TG may be the Aiel's last battle, after (if not before) it they have to give up the spears, or they go on the path leading to Aviendha's vision. The notion that the prophecies could mean the Aiel have to become da'shain once more could come from Rand, to Aviendha (Aviendha is likely to bring up at least the Peace of the Dragon up with Rand). The notion wouldn't sit well with most of the Aiel. Aviendha isn't likely to convince nearly all WO, less of the clan chiefs and it will be even worse when it comes to convincing the warriors themselves. You'd end up with a remnant of a remnant choosing to follow Aviendha on this path, and what will the rest do? They will find a way to commit suicide in a way they deem honourable, death as the only honorable alternative to become like gai'shain for life. They won't want to survive TG if it means giving up their spears after. These Aiel will fight for Rand all the way to SG, and will die.

It doesn't even mean the "remnant" won't "fight". What the da'shain really did during the WOS is something else Rand/LTT knows everything about.

I agree with you Rand won't force anyone anymore. The only thing he's forcing on anyone at this point are choices. He wouldn't turn away the Aiel who wish to remain warriors anymore than he would refuse to help those who wish to return to da'shain beliefs and ways - and in fact one way he could choose to help is by sharing his LTT perspective about the purpose of the da'shain, what they accomplished and why they were not a source of scorn during the WOS. (Or this could come or after TG... one option could lead to Singing having a role in the LB Rand will figure out before the end, once he has da'shain around him again... the other option leads more to a situation were Singing will be exclusively Crop Singing again and a key factor in humanity's survival post TG after yet another summer without agriculture... not to mention tons of animals will die in TG. Food will be very, very scarce afterward. Mixed gender circles to propely use the Bowl of Winds (not globally but to create micro-climate zones (maybe just one) for agriculture - again, Rand would be the source of that knowledge) + Sung Crops by neo-Da'shain may be what saves humanity from starvation). Yeah, they don't have Nyms and won't get any soon. I don't think Nyms are essential. Aes Sedai (Elaida, Cadsuane have been shown with these skills) can do something quite similar. I think Nym were created so singing crops with the da'shain worlwide didn't monopolize so many AS full time.