Currently, the opt-out list import tool would only take into account email communication subscriptions. It would be helpful if customers could also import an opt-out list for SMS subscriptions to preemptively opt out contacts even before they exist in the CRM.
Bulk actions wouldn't work for certain scenarios. A use case is that sometimes Portals have a subscription of paid contacts where all contacts are billable. And creating new contacts to just opt them out wouldn't be as efficient as these contacts would count towards their paid contacts limit.