My take on the Revenant (from a perspective of a video gamer, not so much as concept design) i also posted this before reading the threat so if someone else have posted something similar i would like to say i didn't plagiarize you we just happened to have the same idea/hopes/suggestions for the class.
Type 1: Deals massive damage, maybe even give it a higher crit chance to compensate for it's attack speed is lower than other type of Revenants or there is some sort of delay after a few attacks (so it's not able to chain to many massive damage attacks in row to easily destroy any enemy, or at least a lot of enemies at ones) this type of Revenant sacrifices it's defensive abilities to drastically increases its damage.
This type of Revenant could gain a minor attack power bonus the lower it's health is.
A charging attack, or a massive AoE attack generated by slamming it's weapon in to the ground makes sense with this archetype of the Revenant. (this is your typical heavy attacks damage dealer) I picture this as a massive hulking musclebound figure, especially the arms.
Type 2: Damage output is low, but to compensate it's damage mitigation is very high and so is it's "threat generation" and/or it have the ability to regenerate health (like turning it's rage in to health) in combat to keep itself alive while protecting other party members, it could also have abilities like stunning single targets, lowering their attacks damage or speed, or even the ability to buff it's team mates in some way, again i suggested attack power or damage.
This type of Revenant could gain a minor damage mitigation bonus the lower it's health is.
Adding fear effects/lowered moral effects or the added bonus to add bleed effects on to targets might be a smart way to add the debuff effects and make this archetype unique from the other Revenants and as an added bonus targets with bleed effects could synergies well with the vampire class. (this is you're typical tank) I could see this class type of Revenant not just having a shield, but using the shield as a weapon too and not just using it as a way to mitigate damage. I picture this class as a walking fortress in full plate with a towershield in hand.
Type 3: It's damage output is low and so it is damage mitigation, but to compensate for that this type of Revenant focuses on overwhelming it's enemies not with brute force but sheer numbers of rapid strike in successions to take out it's enemies by forsaking both it's defensive abilities and it's hard hitting abilities to enhance it's movement speed and it's attack speed.
this type of Revenant could gain a attack speed bonus the lower it's health is, or maybe also the higher it's hit combo is without taking any damage.
this type of Revenant could have an daze or stun effect ability it can use on enemies enemies to aide it's team or itself in solo play. (this is your typical damage dealer) I picture this as a more slender version of the Revenant, maybe more like an athlete or martial artist than anything else, no big mussels that gets in the way.