Asaf Bartov, 13/06/2015 02:42:
The (already existing) metric of active-editors-per-million-speakers is, it seems to me, a far more robust metric. Erik Z.'s stats.wikimedia.org http://stats.wikimedia.org is offering that metric.
I personally agree on this in general, but Millosh is trying something different in his current quest, i.e. content ingestion and content coverage assessment, also for missing language subdomains. (By the way, I created the category, please add stuff: https://meta.wikimedia.org/wiki/Category:Content_coverage .)
Mere article count tells us very little and he acknowledged it. As you added analytics: maybe when https://phabricator.wikimedia.org/T44259 is fixed we can also do fancy things like join various tables and count (countable) articles above a minimum threshold of hits, or something like that.
Oh, and the total number of internal links in a wiki is also an interesting metric in many cases: they're often a good indicator of how curated a wiki globally is, while bot-created articles are often orphan. (Locally there might be overlinking but that's rarely a wiki-wide issue.) I don't remember how reliable the WikiStats numbers are, but they often give a good clue already.
Nemo