I run a complete home brew system. I just keep max health low and combat potential low. Every time you receive an injury you suffer a noteworthy injury, die, or start dying. A random human with a knife should always be threatening… because it is. A guy with a knife is actually really scary. A guy with a gun even more so.

With such a system you tend not to have any meaningless fights, and when you do, you make it zany and high stakes and expect at least one person to suffer a severe injury or die.