Wicca as a religion is different to the meaning of witch / warlock etc in the traditional sense. I can't see that having a witch should be taken as the game having religion - nobody looks at the ghosts and sees them as a sign of spiritualism, which is another 'religion'.
And I don't think that the game should have religions. I am an athiest but it wouldn't put me off the game as I think people are entitled to whatever silly beliefs they want to hold. I do however think that it would have the potential for causing offence to others and put the game in the headlines for all the wrong reasons.
We can already build churches (temples or whatever) and cemetaries on community lots if we wish to do so, so there is no need for any religion to be introduced. As for marrying etc on community lots, there's no reason why we couldn't have an 'invite to wedding...' option and specify where and the guests, then go there and click on the arch. It would work similar to group outings so anyone could happily marry their Sims off in the park, mall or wherever they wish
