The biggest problem with an "alignment" system is that it doesn't take into account the severity of one's "conscience." Does it really bother someone who is Neutral Good or Lawful Neutral that dire wolves are eating the cattle? Does it bother a Chaotic Evil orc when he does something to help another orc out? Does it really matter if a Neutral Evil cleric decides to only sacrifice 10 virgins to his god, instead of 12?
Where is the accountability in the system for anyone that is not Lawful Good? It seems as though the virtue of being justice-bound (lawful) and honorable (good) is the only alignment on the spectrum that gets any sort of microscopic inspection.
D&D lacks the variables of "sin" that the alignment system is supposed to represent.
Anyway. I thought it would be cool if there was an article somewhere about SIN in roleplaying games with a list of offensives for the various PHB gods.
I'm not sure if such a task is within the scope of this blog, BUT I do know that if I ever make a fantasy setting again, I'll have sin in there.