I am the developer at my company and I use the API a lot. I do tons of testing. I'll use one of my test emails to add myself to workflows, lists and add custom fields. After a while my test emails get bloated with all the workflows, lists and custom fields I applied to it. It would be incredibly helpful if I could, preferably through the API, either delete my test email or wipe out all of the history on my test email. This would allow me to see more clearly when I go to do another round of testing what my status has been updated to. Also, this would just give us more flexibility in general and allow us to manage our clients data as we see fit. We should be given the ability to do this, being the owners of the content :)
Sorry; this we will not do.
Contact ID is the primary key/foreign key that links just about every record in the entire Maropost Marketing Cloud.
Allowing this type of cascading delete is frought with danger.