Rally Point: Zephon demonstrates that good 4X faction design is really characterisation
Factions. Here are the factions: the aggressive conquest Klingon guys. The evil insectoid hive mind who build stuff and/or have loads of cheap soldiers. The researchers who are probably robots and you usually pick because they can be competitive at anything. The diplomacy/espionage ones (humans, or The Greys).
You know what I'm talking about. You may well have thought of a recent exception too, since we've had a fair few 4Xeses experimenting with some of the standard formulae these last few years. It's been a while though since I read through every word of every faction's description and wanted to play all of them. Zephon captured my interest immediately.