I was also inclined to thinking that Evasion is good mostly only for dismay and frustration, and it's better to focus on armor, positioning, and gadgets.
I experienced situations where poisoning, maiming, and gassing an enemy didn't do a darn thing in several reloads of the same combat—them hitting me consistently in ca. 17 shots out of 20 with even some criticals.
Before you react—yes those were badasses even in CS' meaning of the word, and yes they had some resistances to optical, and poison, but it was 35-75 in each and not like 90-100 for all.
However, later on, this situation with some more common enemies conjured me a content smirk:
Faythe, standing in the open, Evasion 38, Reaction 35, gadget +40% Enemy Accuracy, enemy poisoned (-2 Perception). Results: enemy missing 3 shots from 3 tiles away, and Faythe scoring two reaction shots for 24 HP, crippling with one of those.
I don't know if it can reach the Dungeon Rats' God of Dodge level of extravaganzas someone mentioned here earlier. Then again, Faythe is by no means some ninja with these stats, and IT happened. So, talking about expanding on Evasion...