I’ll start this suggestion with a question:
At what point, numerically, is a player stronger than a Brute? Stronger than a Hulk?
Between mutations, augmentations, (Spells if including magiclysm), and various tom-foolery a budding transhuman can reach some truly stupendous numbers.
I would suggest that, at certain thresholds melee and unarmed attacks be given a chance to proc ‘bash’ or ‘smash’ effects on what was struck. With certain mutations that add or subtract mass such as Huge or Tiny or the like counting for or against one’s actual strength. (A bear would have an easier time of it than even a mighty mouse.)