Data Obfuscation as a transform step
This may be out of scope for this tool, but it could be useful to be able to obfuscate sensitive data prior to loading (or even during the export so that the sensitive data is never even saved to disk). Something like Faker coupled with the SF field metadata would make it fairly easy to generate realistic fake data.
If you do think it's out of scope for the tool, maybe some sort of plugin system for transforms could allow it to live on its own? Obviously neither the obfuscation transform nor the plugin system is a small undertaking, but I think they could make this tool even more useful.