I wonder if just every attack against an enemy's backside should have some kind of damage bonus (like 20%). Bonking someone in the back of the head with a mace is about as effective as stabbing them. Rogue damage needs to be tweaked of course to balance for that.
Don't think spears should have full on backstab, but all scoundrel skills should work with them.
Blackjack is classic thief/thug weapon used from behind. not very piersing isnt it?
Concept of "backstab pierce" is a pure fantasy. Rather make talent "Dirty fighting" which means knowledge of anatomy(lore at least one?) and precise aim (dex at least 14?) cause an extra effect. Double dmg for small pierce weapons or single handed pierce/slash weapon. Stun for single handed crush weapon. Knockdown for two handed crush. Bleed for two handed pierce or slash weapons.
Then Dirty fighting efect/bonus depend on DEX so an rouge with a two handed club (str based) is harmless in face to face, then from behind is pretty nasty.
However, its clear that DOS2 goes way of casters and casual JRPG splash style of combat. Some weapon skills or different weapon dmg types are gone.
Well, ... maby next time.
