Suppose JPMorgan had had the same internal review process, but used a different set of tools. Could a better outcome have resulted?
Let's say that, instead of Excel, JPMorgan had used another tools instead: a simple scripting language (such as RStats)
What would have changed?
Everyone at every step in the writing, review, and use of the model would be able to easily review the code producing the results, which would not have been hidden behind cells in a spreadsheet. More eyeballs on the code might have caught simple calculations sooner.
They would have mechanisms for testing the validity and freshness of the data used, and for automatically selecting and operating on data sets from a variety of sources.
Eliminating manual data entry would have reduced opportunities for transcription errors.
Changes to the code can be meaningfully tracked and reviewed (no DMR, "saving a new version with the date tacked on the end of the filename" does not allow for meaningful comparison of changes between versions and is also not self-enforcing ).