The Vileblade/Venomblade set was good when it was first introduced but seems to have fallen behind lately. I could find no recent builds using it, though perhaps I am just not that good at searching the forums. I would like to make a suggestion on how it can be improved.
Defensively, the set feels a little squishy. Perhaps it could gain %health as a 3 or 4 piece set bonus. For example, 10% health.
Offensively, Amarasta’s Blade Burst (ABB) could receive a flat damage buff. Each of the weapons currently adds 20% weapon damage to ABB, and the 4 piece set bonus adds 40% weapon damage and 120 flat acid damage. Perhaps each of the weapons could also add 60 (or less) flat acid damage to ABB.
Thematically, the set mainly supports Witch Hunter with its Occultist and Nightblade skill modifiers. It supports Dervish too with skill points but no modifier. Perhaps a skill modifier for Righteous Fervour could be added to the 4 piece set bonus. For example, 10-20% weapon damage for Righteous Fervour. This would complete the theme of the set.