I'm working on a system of my own At the moment. Listing factors and stuff here. 

*Atmosphere / Terrain / Weather * Speed / Weight / timing / Height * Perception / Fluidity / Accuracy / Strength *Clothing / Fabric/ Items/ Item Material makeup/ Hair *Muscle Fatigure/ Physical Fitness/ Physical Resistance (Pain, Fatigue) *IQ/ Reflexes/ Reasoning *Personality/ Training/ Physical Gifts *Motion/ Sleep time/ Time Passing/ Land Level *Visibility/ Diet/ Impact Force Type (Slash, Pierce, Blunt) NONPhysical - *Substance/ Effect *Max Effect/ Minimum Effect *Origination/ Manifestation *Times Used / Situations used *Protection / Resistance of user *Power Source/ Power Consumption *Impact Location/ Impact Type (Burning, Freezing, etc) *Conditions of Usage *Resistance to Atmosphere/ Mental Condition *Protection Resistance Type/ Max Resistance / Minimum Resistance *Stance/ Gravity Distribution *Impact Resistance / Impact Absorbing *Physical Substance of Defender *Motion / Force Travel from impact