While Wiccans have probably took the Hebrew meaning of the name Michael as their own, it is indeed a Hebrew name meaning Who is like God. Maybe you're right about the Wiccans, but from what I just read, it turns out that it's Shirley McLaine in "Out on a Limb" who started the "I am God" business that became the mantra of the New Agers. I don't know if Wiccans are considered New Agers or something else though...
I don't know exactly where Wiccans fall into the new age/alternative religion business - but it won't be the first time Pagans have tried to take ancient Hebrew or Christian meanings as their own.