Ignoring the damage buffs which obviously are always gonna make a class better
the deathstrike buff will be noticeable, but i dont think its gonna be enough to push dk over the edge back into the unkillable zone or anything. Prolly not even close.
In open world, itll be best, but in instance where you constantly get healing reduction effects, ds will still heal for around 900k-1.4m on average. If dk is gonna feel less like paper it would probably now have to come by buffing AMS back up a little, Its shield feels quite bad in arenas compared to open world where it still kinda feels like it gets 1-2shot
Very positive change though overall