I think they were short-sighted not going for a 4-axis AP - a 3 Axis one can be counter-intuitive
How can you use a 4-axis or even a 3-axis autopilot approaching and landing on a moving ship with no instrument approach aid? The 'autopilot' s only use then is act as a stabilising device that makes the aircraft do what you want to do, not what the aircraft wants to do.
It comes down to basics. Eyes, ears, cyclic, collective, yaw pedals and instruments. It's the correct use of those senses and equipment that creates a successful operation; not some magical electronic gizmos.
So many accidents are happening, not in this case, where aircraft are destroyed because the person flying them has assumed that the autopilot, and it's associated SOPs, have been followed to the letter.