Well, just compare their respective lines and numbers I bolded in the previous post.
Code:
stat_sec 8,2, no, 0, 0, melee, simple, piercing, knife, 0, 0.075
The purple part is really hurting the unit's attack. 0.075 is a *very* low chance of killing, since Samurai have it at 1, I suspect you are using vanilla values, so make the purple value 1 as well.
After you do that, make the orange part 25, that's the standard for melee units.
Make the red part 3, to make your crossbowmen a bit weaker than the Samurai.
Code:
stat_pri_armour 10, 5, 0, metal
And finally lower the blue part 2 or 3.
That's the layman's approach to unit balancing though, you might want to consider assigning values depending on weapon and armour used, unit "class", etc, instead of this free-form approach.