We should distinguish between the idiom of the prophet and the later theological interpretations of the text.
Ben Adam in Hebrew (Aramaic bar Enosh) expresses the distinction in ancient thought between the mortal and immortal actors in the world drama - between humans and gods in Greek and Roman thought, and between humans and God in Israelite thought.
In the idiom of Ezekiel, ben adam is nothing more than "mortal Joe", an expression of appropriate humility in the presence of the Eternal. Ezekiel has in fact subverted the term from its mythic use, to use it as a literary antithesis emphasising the eternity of God. This use actually results in a diminution the expression.
Because the concept of mortal versus immortal beings that underlies the expression is no longer part Western thought, ben adam is difficult to translate. And because of this difficulty, the translators did as they do in these instances - they punt, that is, translate the words of the expression literally, which in English results in "son of man". The non-expert reader is left with the mistaken idea that "son of man" is some great Theological Concept of OT thinking, when in fact, the opposite is the case.
Ezekiel ben Buzi is a cohen, a priest, who at the time of the exile and the return had a universalistic interpretation on Israelite tradition. However, his prophecy is addressed to the people of Israel, of whom he sees himself not only a member, but an elite member. So there isn't much basis for interpreting ben adam as antithesis to ben brit or ben Yisrael rather that as antithesis to "the ancient of days" or the Eternal God.
The idiom of God referring to Israel as a people seemingly separate people from the prophet that He is addressing is the "perspective view", used especially with Moses, but also with other prophets. This idiom is used to emphasise the prophetic commission, and the prophets righteousness, but does not detach the prophet from the people.
Later theological interpretations, whether Talmudic, Gnostic or Christian, have great meaning and importance to these respective faith communities. Certainly they are all of historical importance in and of themselves.