The higher your Agility the better a tank will avoid enemy melee physical attacks.
This can be a large portion of passive tank potential.
The issue is that the Vengeance mechanic depends upon taking damage.
The statistic agility hinders the main mechanic of the Fighter.
The same thing is true of Blocking, Dodging, and Parrying damage.
I honestly feel that fundamentally the Fighter is mechanically working against itself.
The reset on Rend doesn't really make a difference due to the lack of consistent Vengeance triggers.
There is a trickle effect of the Vengeance mechanic that hinders building the Fighter class overall.
The class is fun and has a good concept but needs to be fundamentally improved because Vengeance just isn't reaching its potential.