Not only is will an imprecise and arbitrary term, Aquinas claims it’s driven by appetites. Appetites are of course emotions, feelings, ect... and not rational decision making processes based on rationally chosen values. These explanations are rooted in ignorance.
It is a novel experience to read someone’s describing Aquinas as ignorant!
I think you and he would disagree about the relationship between “appetite” and reason. He would say that man desires what he thinks (mistakenly or not) to be good, and that reason regulates the appetites (again, more or less well, depending on graces and virtues.)