I would like to see the target getting slowed down instead of stunned.
A stun is obviously prefered, so to compensate, the time being slowed down could be longer than the stun is now.
After that, make all hits (melee and ranged) cause the target to become somewhat slowed down.
Time slowed down should depend on damage received like suggested already but could also depend on weapon type (cut, pierce, blunt).
It could also depend on where you are hit (legs, chest, arms, chest). The possibilities are endless.