Arjuna, 

Your approach to have an idea of a community's activity by combining some metrics is interesting. Also, to compare monthly averages instead of end of year performance is also good.

Increase in database size, number of most active contributors (making more than 100 edits a month) and page views can be real indicators of growth and activity. Is there any way to find database size? We don't have that and many other useful stats after May 2010. Check http://stats.wikimedia.org/EN/TablesWikipediaTA.htm for example. 

Also, any inference based on page views should normalize it based on the population of native speaking people to have a better perspective of the community's performance compared to its potential / size. 

Ravi