We have traditionally understood the divine and the created orders as utterly distinct, separated as if by an unbridgeable chasm. Basil of Caeserea. That's the work of Christ, to bridge that chasm. Others have pointed to more of a spectrum of divinity, a hierarchy, although not emphasised in Isaiah but strong in other OT and extra-canonical writings. What I believe this passage indicates (in Greek, not this translation so much) is that there IS a chasm AND a spectrum, that the title that Jesus had assumed of himself SON OF GOD was considered a divine claim and condemnable as blasphemy. It also appears likely from :
- Jesus' response, which has no quotes in the Greek around the word "gods" (v34),
- the anarthrous theos, god, and the anarthrous anthropon, man (v33),
--> that the allegation in v33 carries indeed the sense of the indefinite article "a".
The " mere " of "mere man" I think is a stylistic interpolation of the NIV that while comprehensible may do nothing to draw us closer to the original meaning of these fascinating verses.