Yeah I've put this change into my game permanently. I like it, although the more viable civic options you have, the better Spiritual becomes. I also increased Free Religion research bonus slightly and made some small improvements to Environmentalism I can't remember. It's quite easy and fairly intuitive to make XML changes, if you haven't tried.
It would be nice though if there were some simple changes we could all agree on here, because there are some glaring imbalances in the game. But of course that would be a miracle...