I found the article well-organized and written. I have a few comments: 1. I like Serfdom in certain situations -- namely, when you have conquered or REXed hard and need to improve your land, when a new improvement becomes available, or when you need to chain irrigation after researching Civil Service and/or for Biology's benefits. Having your workers do stuff faster is very powerful when you need it. If you are running Hereditary Rule, then your new/conquered cities can grow very big, and allowing your workers to improve the tiles faster can make that new city absolutely rocket to productivity. Furthermore, since you advocate a CE, and (as you mention) therefore that Caste System isn't your cuppa tea, why not use Serfdom? It's sure better than whipping away your cottage workers. 2. Since you advocate a warmonger strategy (at least, when feasible), you should talk more about the different uses for spies in that situation. Personally, I love using the spy to cause unrest and drop cultural defenses. This can save you lots of turns normally spent pounding at the walls with your siege weapons. 3. The real power of spying, IMO, is to use as a way to backfill techs from the AI without having to give anything up in a trade. My Gandhi game, below, featured that strategy. As you say, being able to see your foes' research allows you to beeline other paths, then backfill with the AI's techs.