Are There Any Obstacles to Converting to Catholicism?

There are things about Aquinas and his teaching that don't actually have to be believed as he states them. I remember one of my friends who went to Notre Dame, he told me that he just couldn't become Catholic because of the doctrine of divine simplicity. He was only taught the Thomistic view of trans-absansiation. And so he couldn't overcome that in this article, Simpsons Explaining,. If he would have known about the Scotistic view, right? But if you would have known that, then it would have been an option again.