mods_to_dc.xsl that ships with Islandora Batch (and also with Islandora XML Forms and Islandora Importer) contains the following comment:
"When the roleTerm value associated with a name is creator, then name maps to dc:creator[.] When there is no roleTerm value associated with name, or the roleTerm value associated with name is a value other than creator, then name maps to dc:contributor"
However, this note is incomplete, since the XSL code this comment applies to (https://github.com/Islandora/islandora_xml_forms/blob/7.x/builder/transforms/mods_to_dc.xsl#L97) requires that you also include a type="text" or type="code" attribute in your MODS roleTerm elements. If you don't include this attribute, you don't get a dc.creator. I think this is unexpected behavior for many users.
We discovered this while doing some test batch imports with a name element in our MODS with type="corporate" (which falls into the "no roleTerm value associated with name" category from the note). I haven't tested to see if this issue affects custom MODS edit forms.
At a minimum the comment in mods_to_dc.xsl should be clarified to include the requirement for roleTerm type attributes (which BTW are optional according to the MODS schema), and we should consider documenting some of the subtleties of how mods_to_dc.xsl works on https://wiki.duraspace.org/display/ISLANDORA715/How+to+Batch+Ingest+Files.
I'm happy to open some PRs to clarify the comment once we agree that this should be fixed and agree on suitable language. I'll leave it up to the documentation team to consider whether it's worth documenting how mods_to_dc.xsl works outside of the .xsl file.