Dodge is based on Initiative, not Fatigue. Having 2H guy with 130 fatigue won’t help. At last not with base dodge bonus. Higher fatigue will just slow down rate in which initiative drops during combat as you expend fatigue.
In my experience, once you equip your mercs with 200+ armors and 3.lv weapons, you end up with initiative somewhere between 50-60. Sometimes even lover. That’s about 7-9 dodge bonus. And only at the start of the battle. Once you start expending fatigue, it goes down. At the end, you can expect to get about 5 bonus defense on average merc. I leave it to you to decide, if that’s worth perk point. In my opinion, there are better perks.
However if you are building merc which is expected to have high initiative, it may be different case. Say nimble duelist with overwhelm.