I don't mind a way to get more faith from non-religious sources. In fact, some of the design aspects I like most have to do with mixing things up (ie. Choral Music or Feed the World giving you culture/food from holy sites, the tier-3 religious buildings giving all choices of extra bonus, or even the stuff like stone circles letting you get faith from stone). But Goddess of the Harvest to me just adds way too much, and becomes too critical.
Sadly I haven't gotten to try out the +faith per appeal on tiles since that one falls really fast, but to me that feels like a better balanced bonus. At least it means you only get the bonus if you keep appeal high. It might be unbalanced but at least it has a sense of logic to it. I don't understand how harvesting copper gives me a massive faith boost.