Arcanist is nice for its easy energy sustain from IEE and ability to use Vortex of Souls efficiently, but he lacks resistance reduction from Occultist or Demolisher, and lacks damage buffs as well. In your case, i think Conjurer is better, IF you deal with energy sustain (using Arcane Spark, and maybe Scales of Ulcama).
Wind Devil is nice for RR, but you can have quite the same effect from Rhowan’s Crown constellation (that provides great bonuses anyway), saving your points for other useful things (like Wendigo Totem).
Primal Strike is utter trash without transmuter. With transmuter, it can be good for trash clear, IF you possess 4 pieces of Ultos’ set (chest, helm, amulet and shoulders). Eye of the Storm relic is quite mandatory as well. If you dont have that, Primal Strike will suck a bit in ultimate, let’s be honest. That set is way TOO powerful for it. I think, that you should use Savagery for single-target in ultimate, as it’s cheap and deals solid single-target damage.
About Weapon - there are actually 2 options - Rakajax (pure lightning) and Vortex of Souls (Aether/Lightning). The latter is nice because it has 100% pierce, causing great AoE damage. Dont even consider other weapons, as they’re trash compared to these two.
To not waste more words, i’ll give you a link of how your character should look like (items, build, devotions): http://www.grimtools.com/calc/Q2zl59ZA
This is Elementalist variant, but Conjurer is no worse for it.
I’d like to try this build myself, but i lack full Ultos set, and without it, this build wont shine well. Forcewave Witchblade with full Justicar set, etc feels really tanky and powerful, and can be protected from CC. It’s kinda hard to get 80% slow/stun/freeze resistance on non-physical and/or non-soldier characters, because it’s freely granted by soldier passives, items like Boneshatter Threads and constellations like Dire Bear. And from my experience, if you want to success in hard content like Crucible, you must have 80% in those resistances.