Helo,
Of course it's possible to hack MediaWiki further more. But I believe
it's far easier to install a blog software, have it ready and set up in
like 10 minutes.
The aim of the blog will not aim at building a cooperative content,
that's what wiki is for. Instead it will help easily publish important
messages from the dev/admin team to the userbase be it maintenance, new
releases, ongoing changes available on
test.wikipedia.org .
In other words, just because you have a hammer, that doesn't make
everything a nail.