I also am pretty limited regarding theory, but I do remember seeing an online video of a teacher saying how, at the end of his life, Marx was studying primitive forms of society and their complexity.
So I do have to question you in what do you mean by complex societies, because from what I understand ours is a extremely simple one, you are either a worker or a capitalist, there are in betweens but there isn't any other class you can be part of in capitalism.