4.
Psychic/flying cannot work if one stat is too low. 57 base phys. atk. means Swoobat cannot take advantage of a majority of flying moves. 75 base sp. atk. means it has to rely on hurricane or air slash for that special flying STAB. Not very reliant. Also imagine hitting someone with psychic and it deals dollar-store damage. That's embarrassing when a majority of psychic types have a higher base sp. atk. Many of which are not fully evolved, like Kadabra