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
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.