Another offhand reason I peg Elaine as Kumori or at least traitor material is, if you keep looking through the Merlin perspective, Elaine is a dead ringer for Nimueh who was Merlins first love and later betrays him(in one version at the behest of a fae queen) Other versions having her being alternately a seductive magic user who attempts to undermine him or otherwise entrap him for all time.