Horseback units in Sk are good. REALLY good. Wild Horses is easily the most valuable resource. And when you consider that almost all of the rider's skills scale by level, INCLUDING initiative, they are a no-brainer.
Last game I had a stack with several riders at level 18. They were like mini-champions, and whooped the Sorcerer King's ass.
Thus, suggestion:
-Make Riders require 1 horse, 1 logistics, AND 1 metal
-Remove their initiative scaling by level. We can already load them up with items to juice initiative, scaling initative by level is just overpowered, even if you don't spam crusade (I do).