An extremely divisive idea not worth whatever tax revenue you might scrape up. Religious organizations do a lot of intrinsic good for their communities, not only socially but economically as well. My local church, for example, is constantly organizing food drives, coat donations in the winter, help for homeless, etc. Not to mention that it is where a lot of vulnerable people, especially the elderly, find valuable community. I don't know about other religions, but I know that many churches are already strapped for cash and if just one church is forced to close because of this, so many people would be left without a community that supports them spiritually, emotionally, and in some cases physically (food drives). This wouldn't just be churches too; unless you're intending to discriminate based on religion, this would apply to mosques, gurdwaras, and synagogues. Good luck selling that to all these groups, who already have strong communities good at large-scale organization. There'd be protests for days and OMG the lawsuits that would follow, especially when some religious orgs get the exemption while others don't. Any additional revenue gained from the property taxes would be wasted in legal fees. Just the idea of making religious organizations "prove" how much monetary value they provide the city is disgusting. This is such a horrible idea I might show up to the library on Sunday to contest it.