LiveJournalShouldBeNewsInterface. News already has a good interface to threaded, asynchronous discussions; Livejournal has a terrible one.
Distribution. If it were news, the implementation could be distributed across all the users in way that even usenet doesn't manage at the moment.
Instead of having ISPs run huge servers carrying almost everything (...except the one thing you actually want), it would be better if individuals ran their own servers carrying the stuff they were interested in, and had some mechanism for connecting to other people who wanted to carry the same things (probably via a "newsgroup" that everyone carries). It'd be a genuinely peer-to-peer network without large scale copyright violation as its driving force (now there may already be such things but unfortunately they've failed to come to my attention).
A similar idea was reportedly found in Zinque, a BBS on the University of Cambridge's mainframe, which allowed people to contribute bits of their own filespace for discussions that got too large.
Resilience. Without a central server it's hard to launch a denial of service attack. You could still flood the medium (i.e. spam it) though. I wonder if there is a good way to make this hard?
Trust. You have to trust the operators of a centralized service not to subvert whatever restriction you request for your postings. A news-based version would use encryption instead. There's a big key distribution problem to solve.
I haven't figured out how or why WikisShouldBeNews yet, but that's the obvious next step in my plan for world domination through NNTP.
All of this could be done through the magic of RSS; LiveJournal already exports RSS(which sites such as [Lj Find] use), and wikis can too, and several RSS feeds can be aggregated into one (so you could have one big feed for several wikis); recent forms of RSS support hierarchical feeds. Then, yous just need an RSS-to-NNTP gateway, like <http://www.methodize.org/nntprss/> (although this seems to be read-only). This idea won't actually work, of course, because LiveJournal doesn't export comments through RSS. It should do, though - send them a patch!
Given the above description I don't think RSS really contributes anything to the idea.
Similar to WikiShouldBeNews is: Wiki Should Be [AmiCog]. There has got to be a trust web built into the distributed Wiki idea, or it will face the same signal-to-noise problems as news. --Pallando