I have already given a very long response to this post over at Feser's blog. I will say, however, that I too defend a conception of virtue ethics. I am fond of the idea that besides thinking morality only applies to actions it primarily is about what type of people we ought to be. Unlike Feser, I don't go around and throw up very antiquated metaphysics even though I like Aristotle's formulation of virtue ethics. As contemporary philosophers, it is our job to identify those themes most pertinent to our theoretical need while also having an eye to the truth. We need to identify those parts of Aristotle that contribute in a positive manner to our need while at same time jettisoning a lot of it.
Feser wholeheartedly accepts Aristotelian teleology. For him, homosexuals don't share in the proper teleological essence of man. This is a sure way to loose any credibility amongst common everyday orthodoxy. In order to get this project off the ground, you need a very robust and metaphysical view that has been dead for a very long time. Feser has called on conservatives to not be cowards and adopt a "classical essentialist metaphysics".
The mistake lies in several areas. Among them is to think that teleology can only be a principle about nature. First, we might have a teleology as a proposed explanation that comes from our rationality, but is not constitutive of nature. This is a Kantian way to go. We might think that we can construct teleologies for evolutionary explanation since the limit of biology is largely a science of observation. This, however, is contingent upon systematizing our current observations. We might revise such explanations later. Both are more in line with a naturalist bent than thinking that nature is populated by essences conforming to nature's purpose. Even in a phenomenological sense, there are essences, but the principle of the phenomenological insight is to judge a thing's givenness solely without presupposition. This cannot be enacted by having a prior commitment to A-T essentialism. In this way, even phenomenology is more modest in its approach than Feser himself.
Secondly, a Thomist thinks they have reason to know God's law. A Thomist commits the Augustinian mistake--they think God is intelligible rather than siding with Plotinus who sees God as ineffable. If they saw the divine in more modest terms, they would not be so quick to see that God is on their side. For when anyone thinks they can know God's will, it inevitably follows that God will shore up your biases. That's what Feser has ultimately done.