Thomas aquinas's idea of the existance of god through design

Although I believe that Thomas Aquinas was a great ideologist, I also believe that some of his arguments can be discounted with a little bit of realism. The particular point that I have chosen to discount is his proof of the existence of God due to the “guidedness” of nature. With reason and logic this ideology can be plainly discounted as nothing more than a vague stab at the truth.
I would like to explain this idea the way I understood it. He states that all bodies, whether awareness is present or not, are observed following the laws of nature with a certain orderedness that can be attributed to non other than God himself. Also in his writing is the idea that animal behavior hardly ever varies and therefore always turns out good for the existence of that animal. From that he wildly deduces that all behavior must be guided by a force that is intelligent enough to know what exactly the best course of action for any given species is.
First of all, that force, according t...