It did get it to burst into flame when the whirlwind attack is used. It's simply to be a sort of visual reminder that the attack is being used, as there is no Eitri battle cry.
I've also changed a few other animations, such as giving Odysseus a charged ranged attack (also with a flaming weapon), as well as improved the dwarf warrior animation with Brokk's axe and a wooden shield. They all tie into my "The Last King" campaign.