Mmm, I don't see Shamans as a problem, Zecora practically is one. The only thing is what the shaman does, how they do it, and what their focus is. How powerful they are, or what their magic is used for. Primarily Shamans were to do with healing and promoting good health. Abbie talks about the stuff that Zecora does, and that's really key to the way shamans should operate, if anything. Of course, there are many different types of shamans. Rain forest shamans, desert shamans, Native American Shamans, just to name a few, all of them have similar concepts behind what they did, but all of them did it differently. So we'd need to know exactly what kind of shaman you had in mind.