How do we feel about the Crisis system? It seems pretty interesting that Crises are now unavoidable costs of entering a new age, and the skuddlebutt I've heard is that it's an attempt by Firaxis to keep the mid- endgame fresh, since many players end up dropping out due to fatigue.
I think there's a point to be made there. Millenia tried something similar, with "Crisis Ages" created as a result of poor planning or bad luck, but the idea was a bit half-baked in that game. If they're planning on throwing a significant crisis at the end of every age, then even if you're handily beating the AI, at least you'll always have to think about fighting internal struggles. And, well, the bigger you are, the harder those are to manage, I imagine.
Of course, in Millenia, crises were trivial, which took the bite out of them. And if you make them too hard, it might feel like you're punishing "winners" for doing well, which could sting hard, particularly in competitive multiplayer…