There are a few reasons why we clean up our Eloqua contact table occasionally (bouncebacks, unsubcsribers, GDPR, inactivity, reaching the limit for records). The issue we run into is having them re-enter the system as new contacts and no longer be associated to a CRM id. This creates duplicate records in our CRM system.
It would be great to have an integration action/check to see if a contact and/or lead already exists (based on email, but perhaps having some flexibility).
Furthermore, if a contact / lead exists, this check would retrieve the existing CRM Lead and Contact Id for placement on the Eloqua contact record.
In cases where multiple matches occur in CRM, the ability to choose or filter for the more recently modified or created would be idea.