Heh, y'know we could do the pure wiki deletion thing right now, without the links-going-red thing. I've not checked but I bet a lot of VfD candidates don't have many incoming links.
The only problem with articles that could need deletion, I believe, is the chance of them showing up in searches. Diskspace etc doesn't matter. To stop stuff getting searched whenever the index is updated, is just to blank the article.
We could delete VfD again and do this right now. Debates about blanking held on talk pages. We could put a blank articles make links red thing in later.
Dan
PS: "More likely, the tagged articles would just get forgotten and dropped into the abyss, I think" - not if they had a category on them and we had a DPL.