Does anyone know the current status of the design proposal by Ecaterina?
http://design.xwiki.org/xwiki/bin/view/Proposal/Users/UserIndex/UserIndexCards/
In my opinion having an additional cards layout would be a great design improvement to the user index.
I planned on building more or less exactly the same view for our XWiki. But I would save myself the effort and wait some time if you implement it anyway.