Yes, I would think GUCs would be easy to rebook after cancellation since they are paid bookings upgraded to the Z class. My auto-rebooking worked for me so I never had to call in, but perhaps NOLAnwGOLD just got a bad agent.

Anyway, if you have a partner award, you would still expect some flexibility when your flight is cancelled (e.g., if the partner flight cancelled on your day, and there is no award availability, you could still choose to fly on the partner flight the day before or the day after). I realize Delta has to request this kind of accommodation from the partner airline, but my experience is that KLM will grant reasonable requests while AF will not.