I created an empty SharePoint 2010 site collection in which I added many subsites like an Agile Dashboard and a Blog. I wanted to add a Enterprise Wiki but it does not show up in the list of site template. Apparently, SharePoint only allow to add Enterprise Wiki when creating a site collection from the "Publishing" category. It seems strange because for me it makes total sense to have a Wiki along with any kind of site.
Do anybody has an idea how to enable this template in an empty site collection ?