Thank you everyone for your feedback on this item. We recognize this is a valuable feature and are looking at ways we can address it. We do not have a timeline to share at this point.
An error occurred while saving the commentDenis commented
If you create a Yes/No Site Column called "Restricted", and then add this column to a Document Set-based content type, then you will find that you cannot create any new document sets of that content type due to an undefined error.
This is because a "Yes/No" type column for Document Sets and called "Restricted" is reserved - however SharePoint will throw no warning message, just an undefined error when creating document sets of that content type. It is very particular to these three circumstances.
Note that it only affects the creation of document sets through the SharePoint web UI. Creation of document sets is still fine in SharePoint 2010 workflows and using the REST API.
SharePoint should always throw an error message when you try to create a column that will break your site, rather than allowing you to put yourself in this situation in the first place.