Is it the view among observant Jews that God in fact cares about all the intricacies of observance? (as opposed, say, to what is in a person's heart and mind).
Bereishis Rabba (44:1) asks whether it matters to G-d whether we slaughter an animal from the front of the neck or the back. (This question is even more difficult when you realize that in usual shechitah a bird is slaughtered from the front of the neck, but meliqah, a sort of slaughtering done for qorbanos with the kohein‘s nail was done from the back!) Rav concludes that mitzvos only “letzareif bah es habereios — to cleans people with it.”
We do not follow the rules because Hashem cares about the rules themselves. We follow them because they are the Manufacturer's instructions for the proper care and development of the human soul.
Similarly, a Chazan who praises G-d with the phrase “Your Mercy extends to the bird’s nest”, referring to the mitzvah of shiluach haqen, sending away the mother bird before taking her hatchlings or eggs, is to be deposed from leading the service. The mishnah (Megillah 25a) presents this law, and the gemara gives two explanations:
a- “It arouses jealousy of other animals”. b- “Mitzvos are nothing but decrees.”
The implication of the first answer is that G-d doesn’t run all of the world equally, and thus some species have a reason to be jealous of others. It opens room for polytheism or incomplete theism. This is consistent with other items on the list, like the chazzan who says Modim Modim”, saying “Thanks” twice. Which sounds like someone who believes in two gods. (Perhaps out of fear that he picked up some Zoroastrian thought about a demiurge of good and one of evil, as Zoroastrianism was more common among the local non-Jews of the area before the birth of Islam.)
The Ramban (Devarim 22:6) explains the second answer in a manner similar to the conclusion of the medrash. The mitzvah is not an expression of Hashem's compassion. After all, if it were, it would be equally applicable to all of His creatures, not just birds. Rather, it's an exercise He gave us to practice and develop our compassion.
G-d doesn't care about all those fiddling rules. He cares about us, and therefore gave us insight into how to shape ourselves to be everything He made us capable of being.