#3. Central global repository for templates, gadgets and Lua modules (87)
I would love to participate in this - I feel it would bring different language communities much closer together. And great for Graphs & Maps.
#7. Pageview Stats tool (70)
We could even do it on-wiki like here https://www.mediawiki.org/wiki/Extension:Graph/Demo#Using_API - it shows how to draw a graph from pageviews API, and this graph extension http://vega.github.io/vega-editor/?mode=vega&spec=jobs-params can add HTML controls to it.
Awesome list, thanks for getting more community involvement!