One last question - do you plan to replace this metric in particular in the new version? I haven't found that specific information anywhere you've linked.

I'm sorry Anne, I totally missed the point there with my long reply.

Articles per language per population: we will definitely track total articles per wiki project and total overall articles, both de-duplicated by wikidata ID and overall (eventually).  And we plan to offer a more advanced interface where you can divide one metric by another, so you can get "per population" graphed.  We didn't spell this out in the design document but if you click on the navigation model [1] and zoom in you'll see Content -> Total Articles and that's what we're planning to do there.

Edits per user: I think you might mean edits per country from your context, but just in case, we will be tracking edits per user in different ways under the Contributing section.  Active Editors specifically will have more breakdowns and ways to see the data than wikistats does currently.

Edits per country: We had trouble with this metric at the monthly granularity for privacy reasons.  We found potential attacks that could de-anonymize individual editors' locations.  Since this is data we value greatly, we took care to fuzz the numbers and make this very unlikely.  We have new data sanitizing ideas that we're going to work on next quarter because many people could use this kind of data.  For internal WMF staff, we have geowiki which has all these numbers [2].  I'm sorry if I haven't told you about this before, Anne, it definitely seems relevant to your work, let me know if you need help accessing it.