Faith and Reason in Harmony
Kaleb, you bring out so many interesting and important points in this reflection on Aquinas and reason/the intellect. In offering further feedback to you, I would only point out that to Aquinas the power of the intellect cannot be satisfied, cannot reach its own potential, short of ultimately desiring to see God, which requires meritorious movements by the person to do good as well as the free gift of Grace bestowed from God. While both elements need to be present for the perfection of human nature, on the purely human level this desire, and this desire alone, fulfills our nature and is both a truth of faith and a truth of reason.
Since we are called to this end in the power of our intellects, grace is an essential requirement for the soul to perform all of its actions in perfect harmony in order to pursue the ultimate end: the natural desire to see God. In the Thomistic sense, therefore, grace is the indispensable means required to see God. In the power of the intellect the desire to see God emanates from our nature itself and our nature is therefore perfected and not destroyed by grace. A good reference here is: ST Q. 110, Art. 4. Once again, excellent job!
One of the major influencers of the modern Evangelical movement, Francis Schaeffer, likely built upon the reason argument of Aquinas. Sorry to introduce such a segue, but Schaeffer was largely responsible for my return to Catholicism in 1972 after a very brief fling with communism. You've captured the essence of Aquinas thinking on this subject. Nice job.