Stun builds unplayable in co op play due to stun treshold being linked to life

My smith leap slam build breezes through maps. When doing co op play with my friend the build is totally disfunctional. Have to leap several times to stun. From my understanding this is due to monster stun treshold being linked to life, which is plus 50% in co op.

I get that in co op the monsters should be harder but in my opinion this should be mitigated by the boneshatter doing less dmg.

Is this a bug or intended? If intended please consider changing this. Cant co op with my friend and this is how I play most of the game.

Every effect that is not a direct chance is linked to life.

There is a good point for why doing it this way, but also your point is valid of course.
Why increase it? Because otherwise you would play with a team of stunners and freezers and electrocuters and not need to worry about a single attack from a boss that ought to oneshot you.

Why does it work in singleplayer then?
Because of the "immunity" afterwards (which is not strong enough in some cases).

Should it also be on chance?
Wouldnt feel rewarding in the same way.

Good point. Boneshatter does not proc on stun but on primed for stun. So maybe boneshatter can be changed to proc on % of base life instead of % of stun treshold.

Propably chance in relation to damage dealt vs hp (maybe base or maybe playercound modified as everyone contributes to a defree) to that it would guarantee to happen when stun treshold has been reached but the possibility to occure before, while chance being reset to 0 whenever it happened.

The game is still very bad in its partyplay mechanics that each player is hindering the other to make use of the same effect.
Armor break? Yeah, I consume that <-> but I want it to stay!