Since I'm getting a headrush with ideas, I'm going to add a little more to this thread.
I feel that culture shouldn't just be based on the ammount of cultural improvements you have, but also on type of government and on the health of your economy(money in treasury, plus surplus).
So, let's explain this in game terms. For example, you're a properous civ; you have a great economy and many cultural improvements, but your government isn't very popular compared to the others already available. This means you have high culture, because the good overweighs the bad. But, if you're a civ with minimal cultural improvements, a good government, but a terrible economy, this means you have low culture, because the bad outweighs the good.
How does everyone like this idea?