Slightly different idea but how about a class option being available?
Eg Nord Huscarl, would get bonuses to weapon proficiency points to Huscarl weapons for SECONDARY weapons, but big penalties for using any non Huscarl equipment (75% proficiency for example), or knight class, again bonuses to secondary weapon class eg spear if 1H prime but penalties to all non knightly gear.
Would then get themed historical characters, possibly appropriate hybrids, in historical gear without becoming over powerful in the primary weapons. Justified by cultural natural proficiency from upbringing, but in truth who cares if it adds a bit of depth/rpg/fun.
Just a thought.