Migrating to Oracle Flashback for Historization on Oracle 11g
It sounds like Oracle Total Recall may fit your needs:

Regulatory oversight such as Sarbanes-Oxley, HIPAA, and Basel-II, as
well as internal audits, require companies to keep historical data
available for long periods of time. Oracle Total Recall, part of
Oracle's comprehensive portfolio of database security solutions, works
with Oracle Database 11g, Enterprise Edition to help companies store
their data in secure, tamper-proof databases while keeping it
accessible to existing applications

The documentation states that it can support refactoring:

In Oracle Database 11g Release 1, the Add Column DDL operation is
supported with Flashback Data Archive. With Oracle Database 11g
Release 2, the following DDL operations are supported, with full
support for Flashback queries across all associated changes:
• Add, Drop, Rename, Modify Column
• Drop, Truncate Partition
• Rename, Truncate, Drop Table
For more complex DDL –
upgrades, split table, etc. – the Disassociate and Associate PL/SQL
procedures can be used to temporarily disable Flashback Data Archive
on specified tables.