Love the guide and how you went on the fact how unlikely it is to avoid an arrow if you were not expecting it. Also how dammaging crossbows are against heavy armor. There is though a single point which I have to disagree with you.
The entire point that leather was used was to to avoid damage from arrows. Leather armor allowed to soak the power which an arrow hits you with. So a regular bow would not be able to penetrate leather armor. Though it should be possible to penetrate leather armor with a crossbow and a longbow from close aim.
Otherwise, love the guide, and you should certainly write more :)