This feature requests suggests that the data entry metadata should be entered in an extra editing box and then automatically appended at the end of the respective wiki page.
The main motivation for this is to keep the editing process clean - users should only enter content in one window and metadata in another. And if the metadata is automatically appended at the end of a page, the wiki itself is more likely to stay "clean".
Additionally, as also described in
FS#1525, to me the data plugin is a very powerful administrator's tool that should not be available to all users - by appending the data plugin metadata always to the end of a page, it would be relatively easy to keep it from being displayed to users without the necessary permissions.
Of course the Data table, Related Pages and Tag Cloud syntax should remain freely placeable - this suggestion is for the everything followin the ---- dataentry ---- syntax.