I think it would be good if there was a standard way to package user generated content so that it is easier to install. I suggest an archive containing folders that are in the hedgewars Data directory. eg.
tar tf emptycontentpackage.tar.gz > /Fonts > /Forts > /Graphics > /Locale > /Maps > /Missions > /Music > /Names > /Sounds > /Themes
Also, a program to install such files would be good.
I have a script that implements this in Linux (GUI works in GNOME and KDE):