This idea works easily enough in a setting such as Greyhawk or Forgotten Realms in which the gods walk the earth and directly engage with the affairs of mortals, but Eberron's approach to religion is strictly built upon the faith of mortals. That's not to say the deities don't exist; we just don't see them walking across the surface of Eberron and directly interacting with mortals. If the gods actually exist, they simply do not present themselves physically.
Secondly, some faiths follow an idea rather than a specific deity such as the Cults of the Dragon Below or the Blood of Vol. The Lord of Blades is also regarded as a divine being by his followers even though he is a mortal being in actuality.
In addition to the ambiguity of whether or not the gods actually exist, clerics (speaking in D&D terms now) are not restricted from casting spells of opposing alignments to his own either according to the Eberron Campaign Setting [D&D v3.5].
With the above in consideration, one could argue that there shouldn't be any penalties for Minor, Major, and Mortal Sins. Where does that leave the check and balance for keeping devout followers from committing acts that contradict the tenets of their faith?
An alternative is to embrace the concept of a faith-driven power that comes from within instead of being bestowed by an external deity. A Champion might commit an act that is against his true faith, but even having an inkling of doubt about his actions might induce a -2 penalty to his Faith roll. If he commits a Major Sin, it could rattle his faith enough to prevent him from using any powers for a week. If he does something that completely undermines everything for which his faith stands (i.e. - a Mortal Sin), he should feel compelled to complete quest or task of atonement to regain his powers. (This last case could be an opportunity to change faiths as well.)
What do you think? Would you use Minor, Major, and Mortal Sins in your Savage Eberron game, or would you ditch the concepts altogether for your interpretation of faith in Eberron?
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