I was actually wondering if taking the first one in two trees you don't intend on finishing wouldn't set you back from finishing the one you do intend to finish. Good to know.
Not sure I would tell a new player to turn on raging barbarians, but the Honor opener lets you know when a new barb camp spawns, so even on normal barbarian mode, you're never wanting for roaming barbs to kill.
I would think this would be risky, especially if you've got a warmonger who likes to bully citystates. Now you've got to either take the diplo hit everytime they bully a CS, or lose affection with the CS.
Forgive my newbishness, but what's the point in conquering a city then? Keep it! Make it your puppet and convert the lands around it to trading posts. Glory to the Empire!
I'm pretty sure liberating a CS doesn't make it your perma-ally. And you get do get a diplo-bonus for reviving a dead Civ, but does it out-weigh any other diplo-penalties you might accumulate over the rest of the game?
Thanks for the list though, good food for thought.