Missionary gifting again. I wonder if I ever discussed a topic on the internet for this long. But I do notice that we're somewhat listening to each others arguments and we're moving a bit closer to oneanother, so I guess it's not completely useless. I've seen a few of these discussion on the internet that seemed to go nowhere (better not mention any of these discussions specifically as not to curse this thread.
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I have said it a few times. My objection to missionary gifting isn't really based on the exploitation potential of the AI, but mostly on the circumvention of a game rule:
Missionaries cannot spread a non-state religion to a theocracy. The fact that AI-controlled civilisations tend to automatically use the missionary on their cities makes the exploitation potential worse, but I also don't think that missionary gifting of a non-state religion missionary to a human controlled theocracy should be allowed. It would allow this human to circumvent the game rule that a foreign missionary cannot spread a non-state religion to his/her cities.
The rule isn't specifically beneficial or detrimental to the civilisation running a theocracy. It's a limitation with some beneficial effects and some detrimental effects. A well programmed AI and a smart human player will not use the civic when the detrimental effects are worse than the beneficial effects. The civic is a package deal, you get the good with the bad.
But the main discussion point for me is whether it is a good thing to have a game rule that can be circumvented so easily that it is in effect non-existent. I think that is a bad thing. It's bad from a game design perspective and it's bad because it is confusing to gamers not familiar with the intricacies of the game. In that case, I would like to remove the game rule or reinforce it. In my opinion, leaving the situation as it is is not an option. In this specific case, I would vote for reinforcing the rule.
Roland, your opposition to gifting missionaries seems to be solely on the basis that the AI doesn't know what to do with them, so it just blindly uses them to spread religion exactly like it had built the missionary itself.
So, the problem isn't the gifting of missionaries, it's that the AI won't destroy them (if that is a better option for the AI than using them or just holding onto them).
In other words, what you really want is a more intelligent AI, not a ban on gifting. Gifting units (any units) is part of the game. There are ways to exploit the dumb AI by gifting them tons of crappy units, not just missionaries.
So, what makes missionaries so special? Maybe you're exploiting the dumb AI, but you can do that with gifting useless warriers.
If you ban gifting missionaries, you have to ban gifting any unit, for the same reasoning. Or, you fix the AI, which is a big task for "fixing" such a minor exploit that only a human player can use.
As explained above, my objection to gifting a non-state religion missionary to a theocracy is a bit more fundamental. The potential for exploitation does make it worse, but it's not my main ground for objection.
Whether unit gifting is so vulnerable to exploitation that it should be disallowed altogether is a discussion for another day.
Two responses.
1) In the story: So why would the theocratic government even consider accepting this whole city of heathens? Ha. That's like Israel accepting the "gift" of Amman.
2) Gameplay: And it's just as abusive / exploitive of the AI as gifting a missionary. It costs a little more, that's all.
1) You're right that there are many elements in civ that are illogical from a realism point of view. However as explained above, realism based arguments aren't my main objection to the gifting of non-state religion missionaries to a theocracy. I do agree that the game probably could have been made more consistent or realistic without necessarily worsening the gameplay. For instance, I don't think it would worsen gameplay if the non-state religion was automatically removed upon accepting the gift of the city (by a theocracy) combined with a 5 turn rebellion in the city and some loss of population and buildings.
2) As explained above, exploitation based arguments aren't my main objection to the gifting of non-state religion missionaries to a theocracy. Your example of gifting a city with a non-state religion to a theocracy could potentially be exploitive, I agree.
Instead of blocking gifted missionaries, just alter the AI to delete any gifted missionary if it is running Theocracy. This should not be that difficult an AI change. It doesn't have to do any thinking or analysis, just a simple "if unit is non-state-religion missionary and we're running Theo, delete unit" check.
Edit: CvUnit::gift() does the conversion from one player to another. This function could be modified to check that the receiving player is a Theocratic AI. If it is, delete it if it is a non-state-religion missionary.
I don't like having player-specific code in CvUnit, so perhaps add CvPlayerAI::shouldDeleteGiftedUnit(CvUnit* pUnit) to allow for better extension of the ability to detect other special cases in the future.
Automatic deletion of the missionary by a theocracy would have a similar gameplay effect to blocking the gifting of the missionary to a theocracy. However, the human player doesn't know that the missionary is automatically deleted so I guess that this rule is less friendly to new players or players who didn't notice that the foreign civilisation is using the theocracy civic.
Isn't it possible just to insert code to prevent missionaries from being able to be gifted. The fact they can be gifted kind of defeats the purpose of the missionary idea!
In Bhruics unofficial patch for BTS 3.13, missionaries couldn't be gifted to a theocracy. So yes, this is possible. We're discussing whether it is a good idea (I'm in favour of this rule).
This has been discussed ad nauseam. How is this cheating? It's part of the game. The designers permitted it in the game, and it's allowed. "Cheating" doesn't enter the picture. 
