Some of us simply don't trust AFM as a technology:
- it's hardwired to the same 4 cylinders, which may impact wear uniformity;
- switching between V8/V6 and V4 modes is done via valves that can creak or whine;
- the A8 (8L45 and 8L90) trans is tuned differently in DoD (AFM enabled) mode, allowing much more torque converter slip that then triggered the shudder issue much sooner and more readily for many
All these risks for a 1-1.5 mpg gain. The successor to this technology,
DFM is more advanced, but the Camaro did not receive it, and you know how it is with complexity in general, the higher it gets for a component, the more prone it is to fail.