Piwik could integrate an "open source feedburner" that would be a proxy between the original feed URL and the visitor. This proxy could then track data about visitors, what articles are clicked on, etc.
Building such a set of features is not easy, as the code has to deal with lots of edge cases in feed parsing (lots of rss/atom feeds are missing fields, incorrectly formatted, etc.).
News: since feedburner is dead, Piwik could step up as the Open Source Feedburner!
We could get inspiration from this code: https://wordpress.org/extend/plugins/wordpress-feed-statistics/screenshots/
Someone could reverse engineer the extended feed script for Wordpress - https://github.com/WPPlugins/wordpress-feed-statistics
and integrate that into the code. I'd do it, but I just don't have the time... :|