The actual problem about Wraith is her effort to reward ratio for her Decoy. You can just press a button and without any further input (aiming included), you've got a clone of yourself possibly doing quite a nice amount of damage while you are free to do anything you want - flee, help it, hide, you name it. And unless my eyes deceive me, the Decoy can easily clear any kind of proximity-activated traps.
Supernova does require a bit more commitment to make it useful, as you need to actually attack, but still, if you use it at a wrong moment, there is no real punishment.
Compare that to Goliath, who moves himself with two aimed skills and can potentially go into a bad position because of that, root himself with another skill while aiming and the only skill that doesn't change his movement at all is Firebreath, which is much less potent than Decoy. And with all of these skills, the moment you regain full control of Goliath, the ability is no more influencing the hunters (sans FB dot), so all of these require you to commit fully.
Compare that to Kraken, who isn't half as mobile as Wraith and still has to get close to do proper damage (unless the hunters don't know how to dodge at all) risking being punished. Kraken's skills can slow him down when in use (Lightning Strike), require proper aiming or closing distance to the hunters (Mines, Vortex) or both (Aftershock).
And Behemoth shows his weakpoint with every skill used.
What I want to say by all that is that we need to consider something more than just numbers when balancing Wraith. We need to look at what she has to give and what she gets in return.