Glancing through the PDF and focused more on the Shaman (as that seems to be the biggest draw from earlier posts), to me it seems more like a divine witch class more than an Oracle/Witch combo. The spirit rules seem more like the Witch's patron rules than anything else plus the spirit familiar is pretty much the same as the normal witch's familiar. Is the Spirit ability and Greater Spirit ability comparable the Oracles Revelation ability? Also since the Oracle is a spontaneous caster and the Witch a prepared spell caster why didn't they apply the same spell mechanic the used for the Arcanist rather than requiring the Shaman to prepare all of her spells ahead of time? Also to at least give it some Oracle flavor they should have retained the Oracle's Curse ability which I think could have easily been worked into the Shaman class as more of a primitive and superstitious flavor. Instead of a curse call it a taboo and an additional restriction (I think a mechanic similar to the Complete Arcane's Wujen Taboo class ability wouldn't be that hard to retrofit with some word smithing).