One could argue for ever which one thing is "most important" in flying. Based on actual accidents one could say that checking there is juice in the tank might be important
However, I would argue, for general GA flight (not aerobatics) and in the context of a 45hr PPL and typical PPL pilot currency:
If AOA becomes actually critical to flight, and if this happens frequently, then the pilot will end up dead pretty soon.
One just doesn't operate an aircraft that close to the line.