just simple blocking skills for every class example:

person A swings weapon at person B person B uses defensive skill brings their weapon up to block person A attack perhaps still taking small amount of dmg.
this puts defense more in the hands of the player and their skill as opposed to relying so much on stats, pots, and magic sheilds.

every weapon i know including guns have defensive capabilities.

and maybe if get creative and make counter attacks where if you sucessfully block an attack you have a chance to do an automatic counter attack.