My reasoning:
- Standard extractor remains intact (no custom code by customer) and hence for any future issues, OSS applicable
- Custom extractor allows you to extract only what you need
- If in future, a look up is required for cancelled tasks, it would be easier to identify and read
As an alternative to custom extractor - If your extractor is based on tables linked with a simple logic, you can even use SLT to replicate tables and then create a view in HANA and consume that directly.
What works best in your case is what you should choose.
Regards
Gajendra