>>503971345PWS is a joke, it doesn't scale well with spellpower.
Warrior is good whenever you can be on your target, and priests are that type of target. Wars have antifear, so your psychic scream doesn't work, and you don't have any innate way to break distance with wars.
When warrior is on you, you either healing yourself or doing damage. SWP doesn't do much agains warriors with extremely high amounts of stamina.
Shadow is mostly good against other casters, not melee ironically.