Alright, let's say a WoD with a level 3 focus does around 300 points of damage, when the monster is close to death. Let's be optimistic and assume that (due to perfect timing and very high spellweaving skill) the Weaver can cast two WoD before the monster dies. That's a total of 600 damage points.
In comparison:
A Bushido with honor can make criticals with 170 damage. He needs only 4 hits to achieve the same amount of damage.
A mage with an appropriate slayer book can deal (depending on the monster type and its weakness) up to 100 damage or more with a single spell, from safe distance. Six flamestrikes, and he's having the same amount of damage.
Try throwing explosions with an Alchemist wearing a 50% enhance potion ring. Insane damage! And he does not even have a fighting skill!
I could go on.
Now, a fight against such a monster lasts maybe 5 minutes (or longer). While a Spellweaver can try to do all his damage in the last 10 seconds of the fight, the other fighters have the opportunity to do a similar amount of damage during the whole 5 minutes. Believe me, nobody will have problems to get looting rights, if you consider damage over time. I even get looting rights with a character who has 80 archery and crappy equipment.