I checked your GitHub kit_descriptions.tra file, this kit has an extra passive 20% 2D10 knock back attack, hamstring causes enemy slow in movement for 2 round.
I’m thinking with this kind of unique mechanism -2 AC probably not enough. Perhaps armor type can only reach to scale armor and fatigue penalty with each successful hit?
Wearing scale armor so they are dragon knight can move faster than wearing plate mail, fatigue penalty so they can use their special martial art to knock back enemy.
You can also make a connection to let “Second Wind” in “Skill and Abilities” restore some fatigue in a tough fight.