This has one of the best combat systems for most dying light games. However slight improvements should intially be a 3 stance attack system, similarly to the jedi knight academy series you have red stance beating yellow which beats blue but blue beats red, (You could call that High, Medium and Low stances!)
Now add to that actual attack parry and block based on rock paper scissors system for SP/MP for AI and NPC's and other players and you have a realistic feeling system where stance beats other stance first then attack secondary to add decider. This feels more organic to the player and adds more realistic depth to the AI's. Otherwise keep up the good work!