It’s about 10% weaker than using non-set items.
I think the bonuses it adds to the Familiar are nice on their own. The set has been mainly pure Occultist support until now - and I think that at the core, that’s what it remains too. The Skeleton modifiers are bonuses only.
If you want Chaos damage Briarthorn or Primal Spirit, this set converts physical damage to chaos (100%) on those, and as for Skeletons, Mythical Voidwhisper Band can do that.
That’s precisely my point, though.
We already have Lost Souls + Voidwhisper rings if we wanted a Chaos Skeleton build.
We already have Witching Hour
Heck, we already have Harbinger Dominator Blade with Awakened Fiendbinder for full Chaos Mages + Raven.
We’re already flooding with Chaos Cabalist Skeleton options.
And yet, we don’t have Acid to Chaos conversion, which would have been wonderful to make a Chaos Blight Fiends build (and Voidwhisper already gives Vitality to Chaos conversion).
We already have options for 100% Vitality to Chaos and 100% Elemental to Chaos conversions. Fiendgaze Tome is already a good Chaos Cabalist item.
It gives us things that we already have and nothing that we don’t already have. That’s my gripe against this set.
Personally, we have too many options for chaos skeleton already. I would like to see a set that supports fire skeleton+hound, because the good equipments for fire skeleton+hound block each other. Or even an acid skeleton set.
I never used Witching Hour yet, so far. It uses 2 hands, and unlike other daggers/scepters and off-hands, it does not offer substantial skill modifiers. The on attack bonus skill is nice, but temporary. Is it worth it? Also, since it uses both hands it would never have worked in tandem with the Covenant sets.
But I agree, that instead of Skeletons, a conversion or modifier for the Blight Fiend or Briarthrorn would be a better option. Since the set never had any non-Occultist modifiers before as an Epic, they could have add anything from Shaman too.