While I wholly concur with the rest of your post, untransmuted PS is perfectly viable and quite strong at the moment…
Ceno’s List of Why:
Whisperer of Secrets (Bleeding Blade Arc/CoS helmet uniformly outclassed by Bloodrager)
Mythical Wyrmbone Mask. While @RektbyProtoss and I agree that untransmuted Stun Jacks needs a bit more oomph, this is the only item presently trying to accomplish that task and it competes with Light’s Defender. Being so lonely in nature, it itself does not make untransmuted Stun Jacks strong enough to warrant not taking the overwhelmingly-superior LD Helmet.
Mythical Fateweaver’s Mantle. +Static Strike and a proc requiring a Caster Off-hand? Come on, man… (also a proc that gives you 50% more Pierce Resist than anyone could ever need…)
Venomtongue Mantle. The conversion does not really fit any of the supported skills; there’s either no good sources of Chaos to lead to those skills, or what sources of Chaos do exist are for skills that would take this item for Poison, of which Chaos cannot contribute anyways.
Gildor’s Guard…I think. With no base retal and poor uptime on the proc (60% on an on-block proc? That’s an oof, bud), I can’t really envision a use-case for this item.
Heart of Yugol. Truth be told I’ve tried a few Vitality builds with this but they never feel that great and the big highlight of the buff that the chestpiece offers - being some % ADCTH - is hard to make use of with the offered skill selection. I wouldn’t be surprised if there are builds that use this item, because it seems usable, but I’ve never enjoyed any that I’ve tried putting together.
Vestments of Severed Faith. This item would be a lot more impressive if Oathkeeper had Chaos RR. Hint hint.
More or less any of the non-+All Skills belts. But what else is new there?