Give a check on the character simulator and also on the wiki, when you search for the skills , it says what “required Stance” (weapons) are needed to use that skills.
Example: cross guard from Highlander use TwoHandedSword = you need a two handed sword to use this skill.
Catar Stroke also from Highlander use NONE = ANY WEAPON CAN BE USED
so check skills and req. stances when making a build, with this in mind you can spread your horizons when making builds. (sorry if sounded a jerk)
Most of highlander and barbarian have none as req. stance , thats why people aways say that both are usefull in any Swordsman build.