fully agree. buying and reselling is definitely an exploit, because it offers a benefit without drawback or opportunity cost (you could argue there is a minor one, but eh..). let's be real here. the empirical validity of our Civ experiments approaches zero. they are basically all anecdotal evidence. interesting nonetheless, but we shouldn't really hold ourselves to actual scientific standards, because then we really couldn't say much. I fully agree with your assesment. imho the single most broken gameplay feature which constantly gets overlooked is locking the AI into friendship, and the fact that friendship is always 100% renewable when it runs out, and completely deflects any form of attack, and is very easy to achieve.. it makes peaceful play a complete breeze. especially compared to Civ 5 with its backstabbing Lizzy & others. there was a real sense of danger/threat. if you have your neighbors befriended the game ends, simple as that. all of those mechanics mentioned in the OP only help you win faster and more efficiently. friendship locking makes it so that you genuinely cannot lose, as long as you regularly finish before t300. that is much more gamechanging imho. another borderline broken mechanic no one ever mentions is paying AIs to go to war. in almost all of my games I can pay multiple AIs to go to war with my current neighbor for exactly 1 gold. Not even 1 GPT, one gold. The effect of this is that the AIs economy is crippled and they waste their units in stalemates, lose a trading partner, it's generally never beneficial for the AI and a major benefit to the player. Pay an AI to go to war with your current enemy, then after the war drained them, you have a super easy time taking on your next victim. also, please give us back minor gold for disbanding units and great people. it used to be so broken in vanilla, instead of just adjusting the numbers they patched it out. what a shame. there are so many Great Engineers and Great Merchants which are only useful for CV and useless for every other VC. but you still get them, because you cannot pass (the AI takes like 50 turns to generate a GP in the lategame..). it's such a design flaw, and incredibly frustrating, to get a GP and then instantly delete it because it's factually useless. for you sometimes I play games for fun, sometimes for challenge, and sometimes to fuel my (sado)masochistic tendencies. sometimes playing games can even be a transcendental experience.