am I correct in stating that the Report Generator only allows for a cell-array (via Array-based table) to be uploaded and there is no way to handle neither datasets nor Tables?
The Array-Based Table component is a convenience component that allows you to create tables from numeric or cell arrays of strings. The price for convenience is limited content types (for example, no images or hyperlinks) and format options (for example, no coloring of entries).
The Report Explorer contains a set of Table components (Table, TableRow, TableEntry) that supports creation of tables with virtually any type of content and extensive formatting options. You can use the Report Explorer's FOR and WHILE loop components to construct tables whose rows and columns can vary dynamically at report generation time.
As of R2016b, tables and categorical data are accepted in MATLAB Report Generator. See the release notes and doc for more info: http://www.mathworks.com/help/rptgen/release-notes.html