Hi Nathan,
Thanks for contacting Syncfusion support.
We have checked your query. We would like to inform you that, we have already implemented the option “add additional data while uploading and removing files” in Essential JS 2 uploader. The feature will be included in our upcoming main release for volume 2, 2018 which is expected to be rolled out in the mid of June 2018.
Regards,
Karthik R