VR your memory is not clear. The L2 was powerprotected in all coupled modes with the sole exception of CRHT. Height Capture. Which, in our outfit, was mandated not to be used. Other than this, in 4K hrs offshoreL2 I never experienced poor AP performance. There are limits, well documented in the AFM. Operations outside those limits could be exciting.......but until APM 2000 came along, the L2 AP was far better than most of the alternatives.
We regularly and routinely flew approaches in 4 axis. Oddly. We cruised in 3 axis mode to reduce the power modulations in turbulence etc.