It feels so unrewarding to land Shen's sword through an enemy champion

The slow itself is so meh (35% slow when they're walking away from you? I propose 35% period) and it doesn't even do damage. Even the bonus damage is not all that the only part I actually feel does anything is the bonus attack speed.

I'm suggesting maybe if the sword passes through you your armor and magic resist are reduced or maybe it just does damage itself, but what are your thoughts?