Cheers Kim - now all is clear. Thank you. Perhaps it was too many late nights migrating SDE to 10.2.2. I just needed fresh pair of eyes.
Data Interoperability extension can compare two arbitrary data sources without any shared key requirement and drop out unchanged/insert/delete or CRUD sets insert/update/delete over any set of geometry or attribute comparisons. If the scripted approach doesn't work for you email me at bharold@esri.com with sample data and I'll run it.