Playing at emperor level, I've come into a consistent problem which hampers my ability to be effective. I've learned how to REX better than I've ever thought possible, but it only keeps me at parity with monsters like joao, gilgamesh or shaka, and even then it's not something that is sustainable endlessly, eventually the bonuses the AI gets wins out and you're forced to sit back and watch the AI badly settle prime land. Normally, I can overcome this by city specialization and some creative play, but my problems come about when I start next to a warmonger, or an aggressive settling AI who seem to have no regard for city maintenance. Either they'll capture a barb city far from their border and use it as a staging point for further expansion, or they'll settle one themselves and it leaves me all but cut off from that last little bit of land grab which'll likely propel me to gunpowder, and essentially, my military safety for the remainder of the game. How does one go about dealing with this? Is it time to bite the bullet and begin to micromanage my research for trading options, run an espionage economy, or step into the theatre of late-early->mid-game wars? Each has it's own drawbacks, trading is only good for a short while, to postpone the inevitable 'peaking' of your economy as tech become progressively more expensive, espionage economies mean you'll never have a tech edge, and wars before gunpowder tend to be expensive and slow, worse is that I find the tradeoff between expanding at the rate of a shaka comes at the price of military, only to be offset or at least postponed through diplomacy.