I don't see what's wrong with the idea of Borg technology being sentient without an organic component. Isn't that the whole idea behind the Borg, that the overarching collective program enslaves the minds of the living beings it assimilates? And the walls gaining the ability to absorb matter into them is merely an extrapolation from the Borg's use of nanotechnology. If it's assumed that all their technology is assembled from nanites, then it should have the ability to transform or to deconstruct matter on a molecular level. It's basically your classic "gray goo" nanotech scenario. One may quibble about the extremes to which it was taken in Before Dishonor, but the underlying concept is sound.
I'm not so convinced to be frank. The Borg were always presented as a fusion
of organic and technological, and it was that fusion which defined them. In BD, there were essentially no Borg as we had seen them, there was a sentient cube puppeteering a number of disconnected drones and Janeway; it was not a Collective. EDIT: Indeed is it not specifically stated in First Contact that neither the Borg's organic nor technological components can function without the other?
In addition, the Borg's nanotechnology has always been presented as Constructors, rather than Smart Matter. By which I mean; the individual nanoprobes are nonsentient robots designed to construct or reconstruct macro-scale technology according to preset programming or direct instruction. The technology itself is not actually made up of
Regardless, it was actually the horribly contrived "trauma" nonsense I was referring to, the concept that the big bad Enterprise was so mean to the poor little cubie-woobie that it somehow metamorphosed into a sentient creature bent on revenge. First, refer to the argument I make above as to why I find that dubious, but second and more than that, we've seen cubes "experience" circumstances as "traumatic", perhaps even moreso, than were presented in Resistance, yet none of them turned into melty-walled emos.
Anywho, I've just finished Greater Than The Sum, and my sense of despondency has lifted enough after the experience to attempt the Destiny trilogy next. I really enjoyed this one; the technobabble was much more plausible, the characterisation was much more consistent, and the concept of planetary geological processes resulting in evolved intelligence was inspired. Furthermore, it felt like a Star Trek story, although I realise that's a subjective concept.
Hell, I wish they'd put this story up on the big screen in place of Nemesis