Instead of having two tables with single rows representing a transaction as it moves through the pipeline, it has been suggested that we should combine elements of the existing contribution tracking data and payments-initial to create a new payments_event_log table which is more like an event log, containing multiple rows for a single transaction as it moves through the pipeline.

This has been discussed in a few places already:
https://phabricator.wikimedia.org/T86253
https://phabricator.wikimedia.org/T182030#4391109
https://etherpad.wikimedia.org/p/fr-tech-ghost-ship