Sadly, the game is a big disappointment so far. Ok, I live in Europe so I've only played the demo so far, but the first 100-150 turns were always the fun part of the earlier games; City placement, maximizing the science output while expanding quickly. You could do this by founding religions, building cottages, going for the pyramids or by waging really offensive wars (and in BTS, use spies). The different civs and leaders gave you endless possibilities. I often were awake many nights and planned upcoming games in my head.
"Nonsense", you say. "The Pyramids were too powerful", "Cottages were too powerful", "very little strategy was needed". But one thing that you can't deny, is that the first 100 turns were crucial. Getting the economy working in the long run was easy, but getting it working QUICKLY was a tough challenge. You searched for gold and gems, you built the Oracle to be able to chop early Courthouses, you let your neighbour build the Pyramids so you could steal them from him...
It's not possible to come up with such strategies in Civ5, because you have very few options. You get science from population and to get a high population, you need happiness. That's it. Not only is it boring, but also completely unrealistic. The slider gave you the option to invest all money in culture, sacrifying research and military. Though it wasn't perfectly implemented, it gave you tons of option and you could always feel as you had control.
This game kind of feels like a turn-based RTS (paradox!). Build your base >>> collect resources >>> FIGHT! Simply, because if you don't fight, the game will be boring as hell, as there's almost nothing else to do.