Especially, I think the format of wallet.dat needs to be documented. A good practice it to ship the documentation of the internals together with the source code, something missing in the current reference implementation.
So go ahead and document it, volunteer to keep it up to date (that's the hard part), and submit a patch. After the latest source-file re-org, there is a top-level doc/ directory where a "wallet_format.txt" file would go.