It isn't a hard drive space issue. All deleted articles are kept in the database.
Are you seriously advocating that if someone comes and posts an article in main-space which is nothing but an advert for a crappy little garage band or some kid creating an article about how his friends are gay or whatever shouldn't be deleted?
How about instead of deleting them they are blocked from crawlers and all links are rel=nofollowed? That way the information is still available to anyone who knows it exists, but it won't show up in searches. I'd be fine if this is done via an overlay site with Wikipedia as the backend, or better yet, like showdead on HN (which I keep enabled, since sometimes an account gets killed for a single post and the other posts are interesting).
Yeah, so what? No harm is done. Revert bad changes to articles people care about, and ignore articles that nobody cares about. If people actually someone start visiting these 'bad' articles, that means nothing more than you've just identified another avenue for expansion.
That turns Wikipedia into geocities, which is not its role or purpose. There have to be criteria for inclusion. If you have a bunch of articles with unverifiable information, you aren't doing your job as an encyclopedia. Quality matters.
