Whether God had a part in it or not is not the question, since most would agree that the Talmud was composed l'shem shamayim and with God in mind. The question is whether Talmudic law requires supernatural intervention to explain itself. I don't believe it does. I don't know if you've studied the Talmud but it's essentially an effort to justify and further clarify the rules of the Mishna from the text of the Torah with proof texts, allusions and the like.
Many times these proof texts work very well and are indeed impressive and clever, but that should be expected since the Mishna itself was composed with the Torah in mind. Other times though the efforts of the Amoraim (the Talmudic scholars) seem pretty strained and they have to go through several iterations of hair-splitting or "this-case-is-an-exception-because..." in order to come to some conclusion when an apparent contradiction arises. And there are also plenty of times when the Talmudic discussion ends in "Taiku" - where they can figure out no resolution.
Add in the fact that the Talmud itself occasionally cites natural "facts" that are now known to be false to make arguments or simply as side discussion, complements the conclusion that it is a great but still an eminently human work.
If you're looking for another vast and complex system of laws, I'd refer you to the United States' tax code. For comparison, the Talmud is written formally on less than 6000 pages, while the tax code is now more than
