From a British perspective, I'd be very much in favour of a much tighter restriction on charitable status being given to religions. I really do not think that 'preaching' should automatically count as a 'public good'. Maintaining a listed building (as JWs do in eg Manchester), should give some exemptions. And those religions which do offer charitable works should of course get an exemption or be able to have those parts of the religion listed as charities in their own right. In effect, push the charitable aspects away from the religious parts as much as possible. Many religions do this already.
The Plymouth Brethren case here in Britain has already indicated that there is some appetite to look at the idea of 'public good' more broadly. I'd like to see it pushed further, although I think it is an unlikely scenario here without really looking at the role of religion in British society. We still effectively have a state religion after all.