Just to add to the conversation...What's the opportunity cost of Rexxing and is it worth it? I mean, never mind the happiness issue, which can be crippling depending on the map (in my current game, Monty and Askia were offering lopsided deals for luxury resources - it just wasn't worth it).
Because of the low production, there HAS to be an opportunity cost. Is getting out 2 early settlers worth missing out on Stonehenge? Is it worth not getting a few military out for protection and/or gold from barb encampments? Is it worth working unimproved tiles because you haven't produced a worker?
Final question: If Rexxing even needed? In my current game as Alexander, there was more than enough land for me, Montezuma and Askia to settle. Montezuma did start off quickly, claiming land and getting 3 or 4 cities quickly, but so what? He was generating negative cashflow per turn, never had any cash so city-states were out of the question. Askia didn't rex at all. I quietly and slowly got 3 cites, then a fourth....I settled as my happiness permitted.
Here's the kicker....I was smaller than Montezuma, but because the cities in my smaller empire were bigger, my tech rate was higher. When Monty DOWed on Askia, I didn't want him to get bigger so I swoop in with my smaller but more advanced army (I had a couple of trebs and companion cavalary), and destroyed Monty's army. Plus...I had 6 allies in city-states so when Monty tried to send his troop by the allied city-states' borders, they were attacked...
See...Expanding to less cities, but getting more city-states I think is more effective than Rexxing.