I still think the MCAS and stall prevention shouldn't only look at AoA. If pitch attitude is detected to be literally pointing into the ground or even below the horizon for that matter, no system should be sending nose down commands in that scenario. It also shouldn't be sending repeated commands if it has sent N commands after all being overridden by pilot input. I realize perhaps they may have not wanted to over-engineer the system, but honestly looking at the possible failure modes, it seems this system is rather dumb.No. Angle of attack is the *only* direct contributor to a stall. In light planes, the stall warning horn is literally an acoustic horn attached to the leading edge of the wing. It only responds to high aoa, which causes the horn to sound when airflow is interrupted because air is hitting the leading edge at the wrong angle.
By your description, you may be confusing aoa and pitch angle. Pitch angle is the angle with respect to the ground. Aoa is the angle with respect to the airflow.
The reason planes have a "stall speed" is that is the minimum speed the plane can maintain level flight without stalling. But stalls can happen at higher speed during a turn when the aoa is consistently high because the wings produce more lift. When climbing, you are at high power and low speed and can also stall due to a rapid change in pitch.