Although it's the easiest, same row cell changes still conflict unnecessarily.

Interestingly, tables in XML would be easy to merge, as long as they're formatted with one cell per line. E.g.

    <table>
      <row>
        <cell>1</cell>
        <cell>45</cell>
      </row>
    </table>

We use Subversion to manage CSV files pretty much constantly.