Instead of popularity indices, I'd like to see the percentage that a language+framework takes in applications of a certain type, such as desktop applications, client-side web applications, server applications, data crunching, embedded, etc. That way you can spot trends or find alternative languages for a certain task.

Another interesting metric would be the number of open source libraries for the language that have had commits within the last 3 months and whose major semantic version is 1.0 or higher (or some other way to weed out unfinished libraries), sortable by license.