Grand Master's Chapel (15)
Intelligence Agency (1) 4-3 Remember, you don't actually need this to use spies, while you can't faith buy units unless you build the GMC. I wasn't actually going to downvote this and am acutally surprised it collapsed so fast, but I haven't been fond of the arguments on the matter, so taking it out.
My first mission is usually listening post and you need to be level 3 for it to improve so it rarely helps me for my first war that I can use this with. I guess you can Siphon and then send it out but with all that moving it's just too slow.
University (25) 24+1 Still the most valuable building here. It's very rare I don't need science, and at the very least I build it to boost Astro so I can build Potala. Even in games where I build campuses very late, it's a huge boon.
6 turns is too long in a 250-300 turn game?
Well, you have to understand that by the time you build the spy, there are less turns. In reality it may only be 100-150 turns and the last dozen or two turns usually don't matter much for victory.
Intelligence Agency (4) (3+1) This before GMC? Really? What if I'm not aiming for faith or holy sites?
You can capture them, as the AI builds many of them.
And honestly, I don't get the allergic reaction to HS's. They're not bad choices even without a religion, not to mention the AI is obsessed with sharing one with you anyways. It's very easy to find a few spots for good Holy Sites, and if you've already have a campus and trade district in place, why not put it there? The extra 10- faith a turn is often better than many other choices, espeically since you get a discount on districts you don't have many of. Even with bad adjacency, a city could run Holy Site projects and be your empire's sole source of faith. The game is designed for you to build these auxiliary districts to balance out your empire.
You certainly don't have, to, and yea, they're not a good choice. But IMO just writing them off isn't fair because it is very easy to make use of it, and doesn't cost very much.
What if I actually engage in good diplomacy?
Then you'd have allies, of which you can't spy on.
Do you guys build an entire massive army to defend an invasion?
Sure, so you can take a few cities as a counterattack. Troops will easily pay for themselves if you take cities. Pillage a few tiles if you don't want cities. It's extremely high value. Doesn't matter what kind of victory it is. Building units strictly for defense sounds like a waste to me.
Troops also unlock eurekas and era score, and sometimes you want to clear out Barbarians in undeveloped areas ripe for settling. If it's been a while, the barbs can be pretty strong.
The Intelligence Agency always gets value, The GMC however, does not.
There are plenty of games where I've made max alliances and crushed everyone that's not my friend so there's nothing to siphon, or it'd be too much effort. In those case spies do nothing for me and even the Foreign Ministry is better. And yea, I consider myself pretty good at Diplomacy. They're all tools at work. In more aggressive games, I will use spies, but I disagree it's always useful.
I want to say that "what if you don't...." is technically true, but it can apply to anything. I can win by not building any campuses or spies, or holy sites, but sometimes integrating them all in makes for a more balanced game sometimes. If you choose to exclude them, fine, but some of us won't.