The bit that annoys me most (from what they seem to be going for) is I could understand if it was like a tech limit on once you augment a weapon you can't revert it to its tradable form - but the whole 'tinker' that makes it augmented and gizmo that holds the perks being separate things ought to by pass the issue of not being able to remove perks at all.
Sure you can't revert your augmented item with tinker to a tradeable form, but let us remove the gizmos and keep the base augmented it. Heck even make there be a 'price' to doing so - either you pay a chunk of divine energy and get xp only when you take the gizmo off or you get your gizmo/materials back but lose its level ups.
That way you still keep the model of having different weps for different things and gaining xp via levelling up then breaking, but your not locking people into putting 1 gizmo on their weapon ever then thats it - you keep it that way or destroy it.
But then whatever they do it will uberly suck if, as they have suggested, they are blindly marching down the line of needing to break down t90s for unique materials to get the best stuff - that is the perfect way to make the overly rich pvmers get even further ahead of us 'normal' folks in terms of money as the increased demand pushes prices up and expands their wealth all whilst they can afford to break down a few t90s to get the best of the best perks so their kills are faster, easier and better gp:hr whilst us normal folks who can barely scrap 1 t90 wep suddenly find ourselves with sub-par gear (which a load of top end boss groups will decide is not good enough to join their teams) and not a chance in hell of moving forward with them.
And again there is quite a simply solution to make this a non-issue: Do not make any unique material exclusive to disassembling drop only items. By all means make such items give better materials more commonly and make them give a thematically appropriate hard to come by material fairly easily comparatively. But make it so there are other ways to get that material with enough grind or heck even make it so there is a way to get them without utterly destroying the item. Maybe for an energy cost we could 'extract' a weapon to get some materials, but it comes at the cost of degrading the weapon by like 25%, maybe give us ways of using divine energy to infuse lesser items to give them a chance at rarer materials, maybe give items a low chance of generating their unique material just through use.
Of course in all this you'd keep disassembly as the best option, but any number of ideas that would make the materials obtainable other ways would stop them being a giant middle finger to everyone who isn't already rich rich rich.