Project Data Graphs
Both on the dashboard and per project there should be a way to view data/graphs. Showing information such as downloads vs time, user page visits vs time, and engagement (user visits -> page clicks -> downloads). This information will greatly help mod authors know if there efforts are working. As well could lead to better optimization of SEO and user funneling into the site. Which in turn would improve ad rev for everyone.
Additionally, if this data could be exposed as JSON. It could then be download by mod authors to display in there own software. As well be feed into front end libraries that specialize in graph display.
Optionally, there could be settings to allow this information to be shown to the public. Specifically the download vs time graph as this would show users how popular a mod is in modpacks.