Mark Goldblatt's sad, sad attempt at Philosophy Now to say something well-founded about Aquinas must be judged a blatant failure.
First, his argument about the eternity of the world doesn't work, and obviously doesn't; for the eternity of the world is precisely the denial that the world can be 'x units old'; time is a measurement from a reference-point, and Goldblatt is illegitimately taking the beginning of the world as a reference-point (since a thing is 'x units old' as measured from its beginning). Bonaventure was much cleverer, since he argues from the nature of the infinite itself, and argues that it has properties that the world's duration cannot support.
Second, he asks, "if creation means the onset of being, and if the Cause of the world must precede its effect, it would seem that God’s Being must precede the creation of being itself. But if being of any kind precedes the creation of being, in what sense is creation ex nihilo?" and claims that Aquinas sidesteps the question, despite the fact that Aquinas explicitly responds to this sort of concern (e.g., here).
Third, he asks, "if the creation of being is the creation not only of actual but also of potential being, in what sense is God’s pre-creation Being being?" despite the fact that any half-trained monkey can see that Goldblatt is equivocating. Aquinas holds that creation is causation of being, yes; Goldblatt absurdly takes this as meaning that creation causes all being, rather than in the sense that what creation causes in creatures is their being (the whole substance of the thing, as he puts it). So, in other words, the 'being' Aquinas is talking about is the being of the effects; and this is clear from Aquinas's first article on the subject, which restricts the scope of 'all beings' in 'God creates all beings' to 'all things which are diversified by diverse participation of being', i.e., all things that do not exist by nature.
Fourth, he says, "if the beginning of the world can be deduced by ruling out the possibility of an actual infinitude, cannot the beginning of God likewise be deduced?" apparently forgetting that it is he, not Aquinas, who says that the beginning of the world can be deduced by ruling out 'the possiblity of an actual infinitude'. Aquinas, in fact, does rule out the possibility of an actually infinite multitude and the possibility of an actually infinite magnitude. The latter is not relevant to the question; the former is only relevant if the eternity of the world yields an actually infinite multitude. Aquinas's point is that this is precisely what proponents of the doctrine will deny, and it is easy to do so on the Aristotelian position. (This, incidentally, is why one finds in Bonaventure and others the apparently odd argument about infinite souls -- objection 8 in Aquinas's discussion: it is an attempt to force the conclusion that an infinite past yields an infinite multitude. But, as Aquinas notes, it can be evaded.)
Fifth, Goldblatt needs to reread Stump and Kretzmann's article on eternity, since he seems to have missed the fact that Stump and Kretzmann identify several distinct senses of the term 'simultaneity' -- despite the fact that it's the primary point of the article. Goldblatt shows no recognition of the distinctions, and fails to realize that the relativity example is put forward to point out that even with temporal simultaneity we can't be naive.
Sixth, Goldblatt mistakenly assumes that Aquinas's theory of causation requires that the cause temporally precede its effect.
Seventh, Goldblatt argues that "If the world came into being in the beginning, however, the cause of its coming into being either: 1) requires a cause of its own; or 2) spans an infinite duration." But there is a third possibility, namely that there is an uncaused cause that doesn't 'span' a duration. It is clear that what Goldblatt means by 'spanning an infinite duration' is that it be measured by infinite temporal units according to before and after. But this is not Aquinas's view of divine eternity, and Goldblatt's own real argument against Aquinas is extremely lousy, as noted above.
Eighth, Aquinas doesn't absent God from the domain of being; he explicitly says that He Who Is is the most proper name of God and says that God is the "first being, who possesses being most perfectly".