Tim, The MediaWiki Stakeholders' Group recently surveyed MediaWiki users with regards to their use of the software. We summarized the results and the raw anonymous data on MediaWiki.org https://www.mediawiki.org/wiki/2015_MediaWiki_User_Survey. It might be worth looking into.

Additionally, we did ask respondents if they would like to be contacted for follow up discussions. We have yet to do so, but perhaps this question would be a good time to engage these folks. Let us know if you'd like to work together on figuring a way to best handle outreach.

Yours, Chris Koerner clkoerner.com