I've been working on a requirement to either create or update a record in Dynamics 365 based on whether there is a field value match in an excel table. Creating records based on this works a charm, however I have hit a brick wall of darkness while trying to update records in Dynamics due to the limitation with nested foreaches and because I cannot seem to iterate over an array of record identifiers in flow.
This could be easily avoided if we could use the Dynamics 365 alternate key functionality in Flow to identify records when updating from another array or list (say for example my list of contacts in excel).
This would mitigate the limitation with nested foreaches, as you wouldn't need to pull a list of contact IDs from Dynamics and then iterate over each guid in the array to update each record in Dynamics 365. We can upsert records based on alternate keys programmatically, so for us to start adopting flow as a viable non-code solution for integrating data, I think this is quite key.