Something I've seen talked about in a few store owner groups is the ability to flag/take action on "repeat offenders" who place and then refund/return a lot of orders (particuarly fashion/apparel stores suffer from this).
Broad idea would be:
Subscribed to refunds/create and a bulk run manual trigger option for historical back fill.
Task would maintain a "refunds count" metafield on the customer record (options for namespace/key).
Option for "threshold" number of orders when a customer should be flagged.
Option for customer tag to add when threshold reached (tag then allows segment to be created in admin and further actions to be triggered on that tag being added).