Getting a random page (not just article, but any namespace) does not need an external tool as it can already be done within WMF wikis using Special:RandomInCategory/...
What cannot be done on wiki is getting a random article in a category. Erwin's tool is called randomarticle.php (page title is also "random article") but it indeed returns pages from any namespace.
Therefore, I propose that it should be restricted to only pages in namespace = 0.
Alternatively, we can add a dropdown for namespace number, which if left blank would return a page from any namespace but if set to 0 would only return articles.
Getting a random article (not page) from a category is a desirable feature at least on fawiki.