The changes in 7.93 don't really solve the problem. All fields need to be available as different fields will be required on different fields.

One in particular we need available in Quick Letters is Barcode (scannable), which is currently only available in Appeal Letters. Add Barcode (scannable) field to Quick Letters and Export

Currently we have to dedupe queries to be used in a particular mailing using the Segment tab in Quick Letters. And then export each output query individually using Appeal Cards if we want to esport the barcode. When we have 30+ segments for a mailing this can take some time.