Commenting on the universal ability to store a Rage by pressing Utility while holding the Attack button: I'm not sure why it works as it does currently. Storing a Rage is conterintuitive when you can just use the rage normally, especially since the player needs to stay stationary to perform this unnecessary maneuver and leave themselves even more vulnerable. Since it is released when you let go of the Attack button - but you need to be holding the attack button to store it - and you can't move while doing it, this doesn't allow the player to effectively store a 4th bar of Wrath: for example, by having 3 bars of wrath, storing a Rage then picking up an orb of wrath.
TL;DR, The only way to use stored Rage currently is holding the Attack button, storing the Rage, then releasing the Attack button which uses up that stored Rage. Why do that when you can just press the Rage button? Storing Rage is objectively worse than pressing the Rage button.
I believe a good way to fix this is by cancelling the attack when you store Rage, thereby letting the player move freely - maybe have them do a small wind-up animation so it's still not a risk-free action (additionally communicating the charge,) and have the charge be releasable via an input separate from Attack or make charging an attack release the stored Rage.
HOWEVER, I would like to suggest turning this feature into a new mechanic. One idea I had was a bullet time effect or temporarily increased damage, maybe even have it be character-specific; like Sorceress temporarily banishing nearby enemies or Salamander gaining some kind of temporary health / damage reduction? I think this new mechanic should be notable considering it is the same cost as Rage, but I could see it being something simpler like Gunners fully reloading, Salamander refilling her pounce or Sorceress pushing back enemies in front of her.