Siam's gameplay unlock also doesn't seem to be working - 4 temples should be something which happens in almost every game - so I think they're currently the hardest civ in the game to actually get to play! And also the modern civ I most want to play. Grr.
Civ unlocks really weren't all made equal. Some, like Chola and Normans I think have happened every single game. Others are really RNG, and then you have Spain which is just... "Ok. I get the flavour, but really? You thought that was a good idea?"
I'd also like to see some leader start biases changed. Tecumseh not having a navigable river bias when Shawnee have a malus if they don't get those baffles me.