The reason Soul Eater is nerfed, is because we're going to be using soul eater a LOT more than we did before, due to our DPS combo change. (We'd still want to DA soul eater, for the HP healed, but its pretty minimal of a difference, which I think is another reason it was lowered to such an extreme)

Dark Passenger was already really bad, so it BETTER have no MP cost, or be even lower in MP cost than 3.x
Also the DA bonus dmg on quietus is soooo bad.
While we cant boost the dmg on abyssal drain, wouldnt it be better to spend the MP on more abyssal drains, than DA?
Unless the DPS check is so tight, u cant run out of MP before time is up.