Regarding the idea of nerfing swingable polearms, I wonder if the game has certain systems in place to mitigate the possibility of one-hit-kills from full health. In my experience from playing other Cavalry units, I found that thrusting damage while on horseback isn't nearly as powerful as I remember with previous versions of the game, though the Metal Pitchfork seems to hit a lot harder than other polearms while on horseback.
Perhaps whatever damage scaling formulas are being used with thrusting weapons on horseback could be applied to swingable weapons? It'd definitely hurt the Lancer's Heavy Glaive and Courser's Cavalry Menavlion since both weapons already have the downside of not having as much reach compared to most spears.
And with the Heavy Glaive being pretty important to Khuzait's faction balancing, I imagine that they'd have to replace it with a swingable/thrustable blunt weapon to compensate for whatever damage calculations get nerfed regarding the usage of glaives/menavlions on horseback.