i can't confirm the ragnarok saga as i've not read it -- he definitely did NOT use it in the ltd series -- that i DO have.
i agree with the above -- it is thor's IMMORTAL essence -- part in parcel of being a god. i see no reason why bill (who is possessed of an equivalent of thor's POWER) would possess a godforce. odin gave him the hammer -- he did not make him a true god. to believe otherwise this would suggest that when supes held the hammer he could have shot a godforce blast because he too was worthy. same with anyone else who's held it. i don't believe it.
i've asked the question before and no one has ever shown evidence of bill using a godforce blast. i am still waiting.