Instead of having a flat strength or weakness power level you could instead have it as a level system in terms of:
-Major
-Normal
-Minor

These cards would help to give more options to players and narrators with how they react to situations. These levels would also have different impacts on challenges, for example playing a major strength card would fill in two or three pips instead of just one since its a major card while a minor card would only act as either an equalizer to negative cards or fill in one pip.