The proposition, "God is perfect," is probably heretical. In all of its usages "perfect" retains some of its literal meaning, "brought to an end, completed." And hence the word _could_ (I've never explored the matter) carry the implication that at _some point in time_ God was incomplete, but now has become what He Is.
That way madness lurks.
P.S. I've just discovered by accident that the complete text of Canto XVI is available for download at the Poetry site. That Canto is a marvel even when pronounced by the synthetic voice of ZoomText. Il miglior fabbro indeed.