PoE Spawnbroker builds

I'm working on an Eye of Winter build because frozen orb was awesome in D2 and I want to try it out here. With the nerfs to everything, I figure this is as good a time as any to experiment with a new skill! I see two ways to build this, you can either go cast speed + crit or you can go unleash and ignore cast speed. I built both out in PoB, but cast speed seemed more promising. Eventually you can probably transition into dual void batteries once you get enough currency. I went Occultist here, but Assassin would also probably work well. Deadeye might be good too! Thoughts? Improvements you w