Bengt Lemne from Gamereactor has interviewed Ed Beach the gameplay designer of Firaxis for the Civilization 5 addon Gods and Kings. They were talking about religion, diplomacy, and combat in Civ5:G&K. Here is the video of the interview and a transcript, which has been edited for style and clarity:

Bengt Lemne:
Gods and Kings, I just got a demo, and I thougfht it is similar to the press release about it: A new expansion, they are writing about religion for Civ5. For me it's not a huge deal, because I played religion in Civ4. But vow, when I saw the demo, that's gonna change the game as I play it, completely.

Ed Beach:
Yes, we looked into what religion was doing in Civ4. We thought, hell all the different religions in the game are sort of of similar. There isn't really a big difference than just a name that is tied to you pushing your religion across the map. Everyone gets the same benefits out of it.
We thought: It would be a much more interesting game play experience if the religions that you are creating effected the game world much more. So that you could decide: "I'm playing a culture game, I'm gonna configure my religion around a set of beliefs, [that fit my culture game]." In Civ5:G&K each of our religions gets five gameplay effects that we call beliefs that you can put into your religion. This way you can configure your religion so that it complements your strategy. Your religion may even complement the civilization you have chosen.
You've got a rich set of bonuses for exploring the strategic path through the game. And that's what we find exciting. We have been testing the new religion system for months now, and we are still finding new strategies, new ways to play the game. And there are hundreds of more combinations out there that other people are gonna find. So we are very excited about it.

Bengt Lemne:
Yes, I think religion was one of those things, that was on top of everything else. You didn't really think about it. It was just there and ate other things that you would do. You didn't really pursue it, like a thing on its own.

Ed Beach:
Right, religion was there and gave great historical context and flavored everything. You had interesting situations like England being entirely in trough with Buddhism that people found widely entertaining, but religion didn't really have a big gameplay implication.
Now, you have to make a decision early in the game: "Am I gonna pursue a religion or not." If you wanna pursue it you wanna be there right with the AI getting to the religion founding and creation as early as you can, because there is a limited number of beliefs in the game. There are only about 50 beliefs in the game. And whoever gets them first, pulls them from a pool of beliefs. So that no-one else can get them. Based on where you are on the map, you might get some beliefs that are important to the terrain you are in. The beliefs might be important for the strategy you are pursuing. Even so it is a religious system, if you put the right beliefs together it can help you in military conquest.
We find also reasons either to go for religion or not. If you go for religion you wanna pursue it heavily. It is also okay not to go for religion, because that means you don't have to invest in shrines, temples, and some of the other activities. however if religion comes to you get quite many benefits from it, even so you can't chose what the benefits are, you still get a tangible boost to your civilization out of it.

Bengt Lemne:
And the problem is that it might cause some problems, as well. That you didn't count on. For instance you just chose that just war thing y and someone can easier invade you.

Ed Beach:
Right, you have to pay for careful attention to what the other powers choose and do with religion as well. It is not just about what you have chosen yourself. It is also about whether the others have chosen a belief that could be harmful for you long term. One belief that we didn't show in the demo is particular interesting. It is called Holy Warriors. Normally, you spend faith peaceful things like missionaries, and building Cathedrals, Mosques, or Pagodas in your cities. But if you choose the Holy Warriors belief then the faith your people are building up can be used for your military. Through the Renaissance, but not late in the game, in this heavy crusading period of history. All the sudden, you can use your religion to force your people into great military action. That is a dangerous belief, especially if you have the AI at your borders. So, you wanna know about that.

Bengt Lemne:
On the other side of Missionaries, you have the Inquisitors, so you can stomp down on any religion you don't want to have in your nation.

Ed Beach:
We thought, maybe we should trow an achievement into the game, so that the Spanish use the Inquisitors that would be an interesting thing to have succeeded on. But the Inquisitors are the Anti-Missionaries those, instead of adding religious pressure on a city, take it away. In this case they take it away from the other civilization that is trying to push their religion onto you.

Bengt Lemne:
You touched it. It is quite interesting that religion plays different role during the different eras of the game. It also feeds into other systems you are bringing into the game like espionage, which playsa bigger role later in the game. How does this flow into the game?

Ed Beach:
What we thought, was the game Civilization has always been terrific with establishing a sense of the sweep of time, and the sweep of history. And you see that in the game in a lot of ways, especially with the military units. For instance, you just start with archers and bowmen and they can shoot a range unit, shoot arrows across a river, but that is not as cool as having fighters, modern armors, aircraft carriers, and stuff like this, later in the game. So the military side of the game you got already a great sense of progression.
But we felt the diplomatic side of the game does not change much. You could form friendships, you could denounce people. And that was always the same at the beginning of the game as in the end. Well, you can still form friendships anytime during the game. But we wanted to introduce some elements of changing the nature of diplomatic relations through history into the game.
And that's now what you see very early in the game. The most important thing diplomatically is fighting for territory. Who is settling where.
And then in the middle of the game when the religions have formed, people are very focused on who is spreading a religion over my civilization that I don't want there. And maybe if they are not fighting a religious game then they may be even happy that someone is spreading a religion to them, because then they get the benefits from it. So in the middle part of the game religion is an important diplomatic factor.
In the late game the new espionage system is obviously a key driver to diplomatic interaction. You can catch people spying on you. People can get mad about that and you can promise not to do it. But you can go back on that promise and break it.
We also added an ideological component where your choice of late game policies put you into one or another of three different ideological camps. And that gives the feeling of a cold war. Eastern block versus western block. Maybe this is not quite in the sense of progression like the military part of the game but there is a lot more going on diplomatically than there was before.

Bengt Lemne:
That brings us into how you interact with city states as well, there are now a lot more options. It is not just about bribing them and that.

Ed Beach:
Exactly, we wanted to make sure that gold was deemphasized as a way to influence city states and we added a new quest system that we put into place. It builds on the interactions, which you had with city states for clearing up Barbarians and things like that, in the original game.
We took that quest system and made it much richer and deeper. City states can have up to three quests. They can have quests with more than one power at the time. There is a wide variety of types of quests. And late in the game, the city states are tied with the rest of the espionage system as well. Your agents, as well stealing technologies and getting intriguing from others major powers, can go into those minor powers the city states and work with them as the way as the soviets and the US might have worked with a third world country during that cold war era. And all the sudden, you're either reading the elections in the city states or maybe you are even trying to throw a government out of power entirely with a coup. It can be dangerous for your spies to do that, but it is a great way to gain influence quickly. You can see these late game UN elections to try to determine victory. It is going to be very crazy with coups and spying and the quest activity going on at the same time.

Bengt Lemne:
So we touched on most of the changes. Is there any particular new thing that you feel we've left out of this interview that you think we need to know about?

Ed Beach:
Well, we should talk about what we have done with the combat system. The combat system has been changed regarding land combat, how all the units are introduced in the technology tree, and how naval combat works. So let's just go these, quickly:

• We introduced a whole new upgrade path for ranged units. It does not end at the crossbow anymore, but you can now go up through the gatling gun to the machine gun.
• We changed the hit point scale for all combat units. So there is now more fidelity over that system. It is now on a hundred point scale instead of a ten point scale. Which allows us to better fine tune the pacing of combat which was a little bit too quick.
• With the naval units, naval invasions just took too much space on the map. So we allowed embarked land units to stack with naval units. Which compacts navy formation.
• We also split naval units into two types: Naval melee and naval ranged units.

So there is more going on with combat. There are more strategic decisions about whom you put into the front line and whether or not you are actually trying to use your naval melee units which can attack naval units like units on a grassland tile just on the shore like a range unit. But the great thing is they can attack coastal cities and either pillage them for gold or capture them.

Bengt Lemne:
Right, you are bringing this up later this spring.

Ed Beach:
Yes, it should be available later this spring to steam and online retailers. We are excited to get it out.