I tried making a Chaos CDR Caster build last week as a ‘somewhat educated’ newbie - and every option I tried just felt so clunky and un-fun.
Warlock is fun and has good synergies, but zero relevant RR from masteries.
Purifier has promise but it’s so point hungry, plus neither of the Exclusives are of any real use except for some peripheral advantages like Physical Resist or reduced incoming Damage.
Pyromancer would possibly be OK but only once you get chunky Fire->Chaos conversion for almost every skill you use, plus it feels like you’re going 70+ points into Demo just for Hellfire Mines plus the last node of the BWC line.
Deceiver, same critcisms as Purifier except you get even less relevant RR.
Of all the playstyles of the above I tried, Warlock makes the most sense, but lack of RR just kills it.
So add my (pointless) vote for adding Chaos RR to something in either Arcanist, or to Bloody Pox.
Or just put some on Devouring Swarm, Blood Pact or Entangling Vines and get some great mutual damage synergy for a Chaos/Vitality Conjurer.
I have a bank full of great Chaos legendaries and no real ability to use them!