The “active” component of spreading religion - using units and religious “combat” - is absurd tedium. I truly hope that next time they can think of a better way for the player to manage religion than relying on units.
This is my own opinion of course, but I think victory conditions shouldn't be entirely passive. I like an active component. With science, you have passive tech progression and then the active component in building the space race projects. With culture, it used to be overwhelmingly passive except for the race for GP and artifacts. It was ok, but you could easily find yourself in the doldrums, just hitting next turn waiting for the numbers to add up. It was painfully boring. When they added in a bunch of tile improvements that gave tourism, the national parks, and the rock bands, CV became much more enjoyable to play. An active component is needed to help secure that victory late in the game. This is true of religion as well.
Something I think is missing in both Civ5 and Civ6 is the concept of a State Religion
I've seen this idea from time to time. Historically, we could think of Henry VIII and the Church of England or the various emirates and Islam. If we wanted to broaden it, Soviet communism had no religion (or the State itself as God) as the "state religion." Atheism could be supported in the game. In Civ 6, the parallel might simply be that if you founded a religion, that is your state religion. If you didn't found a religion, you're the battlefield. You don't really get to choose which seems logical. There has to be a trade-off with religions. If I choose to focus heavily on science or building a big army for early warmongering and miss the religions, I did get some advantage for my choice, but my opportunity cost was the right to define my own religion. That design works for me. See my reply to Zaarin (below) for a bit more.
2. Make religions founded dynamically and give players the option to adopt it as state religion, tolerate it, or suppress it. Make religion have stronger influence on diplomacy and encourage the formation of religious blocs.
3. Don't like your religion? Give players the option to reform or schism their religion or develop heresies. This is a great opportunity to bring in ecumenical councils.
I like the idea of having players get a bit more control over religion, especially if you're in the battlefield because you didn't make a religion. In Civ 6, you can make missionaries and apostles of the religion you like to help spread it in your cities, but that's a very clunky mechanic. If we changed it so that the non-founders who still wanted to play the religion game could invest in faith and force a schism or reformation to create their own religion, that would make things more interesting. If you don't want to invest at all, you can still do that, but if you did want to, you'd not be locked out entirely. You'd pick a founded religion, keep their core beliefs but get to select 1-2 ones you want. This might be a good place to introduce atheism as well. You could opt for atheism as your preferred religion and repress other religions (passing up their bonuses too) in exchange for a state loyalty bonus or something so if you're warmongering or have a massive empire that's outpacing your happiness/loyalty, that could be an option.
I also really liked your suggestion about diplomacy. That's such an important thing to consider when dealing with much of history. In Civ 6, we get this idea but it's late in the game with ideology. Your pick of tier 3 government can break longstanding alliances. But if you think about religion, Europe went to war for centuries over Catholicism vs Protestantism and went to the Holy Land how many times to war against Islam? It should be part of diplomacy. The idea of being able to designate whether you tolerate or suppress another religion is a great dynamic, and something you could negotiate. And having diplomatic disagreements flare up if you don't tolerate religion is natural.
My only other thought is to not complicate it too much. I'm not accusing you of that, just expressing my own opinion that one thing civ does right is keep the mechanics simple so they're easy to learn and play with. I've played other games where they make such complicated religion and culture and dynasty systems that it's overwhelming.
Agreed. I feel like religion should ideally be like gold in these games - a flexible engine for pushing for other victories, but not a victory in and of itself.
I actually like it as a VC. Historical parallels exist in all 3 of the monotheistic religions, where 1000 years of people after the Messiah returns or the global Caliphate is proclaimed, etc. Convincing the whole world to adopt your spiritual view of the world would be quite a feat. It's a peaceful version of the Domination game, if you think about it. Games are not won by all the VCs, but just the one that gets done first. Religion can easily stagnate, just like Domination, and if it does, there are other options. The one I'd like to see added is an economic VC. I miss that one from old school Alpha Centauri, and with the corporations mode add-on, I thought they laid a lot of groundwork for how to do such a thing.
I don't think it hurts to offer the option as a field of human endeavor, to convince the whole world to share one set of spiritual beliefs, even if the game is won by other means most of the time.