Currently all Field Processors and Export Entity Filters for Migrate Default Content Export are regular classes that don't integrate themselves into Drupal properly. This creates a lot of extra code in the drush command that really shouldn't be there.
We need to refactor all processors and filters as plugins with a plugin manager for each of them. This will clean up the source code drastically and has the added benefit of allowing the system to be plugin-able.
Implement plugin managers for Field Processors and Export Entity Filters.
Fixed
3.0
Code
I have this implemented in https://git.drupalcode.org/project/migrate_default_content/-/merge_reque...
I will merge and mark the issue as fixed.
Automatically closed - issue fixed for 2 weeks with no activity.