I would be good to be able to add contacts to a Marketing List from the Customer Journey flow. It is already possible to add contacts to a segment, for example when a Marketing Mail has been sent to that contact - but it would be good also to be able to add the contact to a Marketing List. 

Business case - Adding contacts to Marketing Lists is possible in MDM, and adding this functionality would make it easier to re-implement existing marketing flows as Customer Journeys in D365 Marketing.

We have discussed the possibility to use the "Launch Workflow" tile to do this - and creating a workflow that adds the contact to a marketing list. But as I understand it, there is no "out of the box" way to add contacts to marketing lists from a workflow, so this would mean that we would have to rely on third party components for doing this, or implement our own CWA. So, it would be easier if this could be done directly in a Customer Journey.