The gain is the potential for increased diversity. I mean 'Polytheism=Hinduism'?

Don't get me wrong, Hinduism is a very important religion, but surely players should be allowed to have something like the Ossirian Pantheon, Olympian Pantheon or perhaps the Norse Pantheon as their chosen polytheistic faith. I just don't see why we need to
uneccessarily restrict our choices when those choices could make for an intriguing game experience. All you need to do is ensure that you don't dilute the importance of religions by doing so-which is why I made the 'Cultural Exclusion' suggestion.