I recently tried to build a militarist culture around Huns and Mongols and their unique normadic units. I played on Metropolis difficulty and crushed the AI so its hard to tell if it is balanced, but I can definetly tell you that its so much fun. Having self sustianing raid parties terrorizing the map feels like a good payoff for the inability to create or expand new cities and the entire playstyle, being normadic and having short ranged bows, makes combat and meta-war strategies feel unique from other cultures.