I agree with both of your points.
First, I think his reasoning is pretty basic and logical: IF Jesus is God (I disagree but lets assume for the sake of argument), then if follows the Mary is the mother of God. His point that mother is not the same as creator is a distinction that answers the objections that Protestants bring up.
And I agree fervently with your second point as well -- there is a huge problem in saying Jesus is God. I agree that the Nicene Creed, at least as I have read it in English translations, is not always worded very clearly. This is especially true when you consider that it is impossible to translate Homoousios into English, and this is the very word that the theology of the Trinity rests upon.
You might be someone that I can talk to about this. It would be nice to have someone to talk to about it.
There's a theory that the in the Greek that is translated as "the Word was God," the word "God" functions as what is called an adjective in English. Considered in the context of the whole Christian Bible, I would take that as saying that it was like God in every conceivable way.
When Peter says that Jesus is the anointed one, the son of the living God, and Jesus praises him for it, I take that as referring to the king that God told David He would raise from his descendants, saying "I will be his father and he will be my son." It has nothing to do with the way that Jesus was conceived.
There's a theory that the earliest Christians worshipped Jesus. I personally think that it was actually Jesus who taught them the practices that looked like worshipping a god. In the gospel stories, he
is a god as much as any Greek or Roman god and even more, with more authority and power over human lives than any of them, besides being real. I don't think he actually claimed to be anything that was outside of the range of Jewish thinking, but some Christian followers either didn't understand that or didn't think that others could, so they tried to explain how the Christians could be worshipping Jesus and God at the same time without that being two gods, using Greek philosophy, telling themselves that Greek philosophy was actually inspired by Moses. Different ones explained it in different ways, and various factions formed around those. That led to public feuding which threatened the ambitions of Roman emperors, which they tried to repress with an agreement signed by some of the bishops. That failed miserably the first time, but maybe halfway succeeded on the second try.
The Nicene creed might possibly not be outside of the range of Jewish thinking, as it was understood by some people, but one problem now is that in the minds of many people, possibly most of them, it has been replaced by the Trinity triangle, which totally mangles it and oversimplifies it to fit it into a cute, clever and easily remembered diagram, and all the feuding is about that instead of what the Nicene Creed actually says.
(later) I know that it's inaccurate to talk about "Jewish thinking" in the time of Jesus, but I can't remember what to call the religious system.
(later) Oh. Maybe it isn't "Jewish" that's anachronistic, but only "Judaism."