Of course one person's blasphemy might be another person's canon
Uh...
I think the
best portrayal of God in comics is currently in Clive Barker's Next Testament, over at Boom. It explains where he's been since creation and his intentions upon returning. The last issue featured him at the center of a massive orgy in Paris.
We're not talking about a finer point of history or scripture. But malicious delight in a portrayal that degrades and deliberately tramples on what is sacred to others.
So in that case comics should never portray anything in a negative light as it might upset someone.
Christian beliefs are no more important than other religious beliefs, political beliefs, sexual orientation, gender, musical taste or sock loving.