I also was bothered by this some time back, so I took a look around the CS. This is what I found; Bows have the ImpactDataSet "WPNzArrowImpactSet" which determines the way the arrows will behave when colliding against different materials. Within this setting, each type of material is matched with it's corresponding phys behaviour. "MaterialArmorHeavy" is matched with "WPNArrowVSMetalImpact". All it takes for the later to reflect arrows is to change it's "Orientation" field from "Surface Normal" to "Proyectile Reflection", and it works, it in fact makes arrows be bounced away. Now the problem is that the game does not apply this "MaterialArmorHeavy" classification to heavy armors, and there is no way to add this trait to armor sets nor any other item or addon, it can only be applied to races and creatures that have the "Impact Material Type" in which to select this classification. I was disappointed, because the only way to have arrows bounce was to mark my character's custom race as the arrow deflector. I did it though, it works for me since I never go into combat without being absolutely covered in plate, so arrows that hit me are deflected, as are ice spikes. The obvious downside of this is that if I am ever surprised by attackers when I am not in my armor, and they hit me with an arrow, it will bounce off my character's skin or clothes as if it was plate armour, which will indeed look absurd. As much as this works fine enough for me, this patch of a solution is kind of lame and I am willing to work with anyone also looking for the ideal solution to this problem. It is as simple as to find a way, with SKSE or hidden within the CS, to change the character's "Impact Material Type" field to MaterialHeavyArmor when a heavy armor set is equipped. Or to find a way to apply this to the armor pieces themselves, but I looked everywhere and could not find it.