The general consensus is that getting a religion is not worth the heavy initial investment required. There is also too little incentive to spread your religion unless you are going for religious victory. Historically, religion played a major role in diplomacy and the game should do more reflect that. Mod idea is simple. Make it so that everyone (not just religious founders) can get the "convert to your religion" city state quest. Yes this would mean that civs who haven't yet founded a religion would miss out.