I mean the problems for interpreters of the book:

1. 1.18ff is referring only to pagans and what they do with the “light of nature” or “general revelation.”
2. Those who are “without law” are completely ignorant of all commandments; they have never heard them.
3. The “work of the Law” written on the heart must only refer to the nag of suppressed conscience against general revelation.
4. The statement that God “will render to each one according to his works” must be divorced from every covenantal context in which such a statement is used. This can only be hypothetical works righteousness.
5. The Gentiles who become regarded as circumcised are entirely hypothetical of a sinless person.  Paul does not believe that any Gentile has ever or will ever come to be regarded this way.  Why he even brings up the possibility, when all he really wants to say is that no Israelite ever continues to be regarded as circumcised, is left something of a mystery.

Some of these ideas are improbable.  Others are impossible.