Good point.
Melee Monks don't wear armour in the first place - Yes they're in a bad spot currently but this isn't going to make them worse just not going to help them.
I can give you one reason for not going flat out dodge/evasion - DODGE CAP!
If I'm going to get hit every other attack {or more likely 2 out of every 3} and I get one-shot by every hit then I may as well have ZERO Dodge!
Dodge is a complete waste of time without enough PRR to make it so that you can survive at least 2 hits in a row!
This is the real problem with Melee Monks - Even in Earth Stance the best PRR they can get without Past Lives is around 95 {Nowhere near enough!}. In any Stance other than Earth forget about running anything harder than EN!
I hadn't thought of this but good point.