I'd like to see a lot of changes in the way wonders are handled in the game.

First of all I'd like to see more prerequisites to build certain wonders like the right religion if it's a religious wonder, the right cultural group, maybe the right traits for some wonders and maybe built on the right terrain type in some cases.

Second: I want it to be a race for the tech's to build the wonders rather than building races. The first to get the tech will be the first to decide whether to build it or not, no one else is allowed to start a wonder someone else already is building.

Third: Minor extra bonuses should come if it's the "right" nation that builds a certain wonder - the pyramids in Egypt etc. I don't want them to be cheaper.

Forth: No wonder should last forever. It often just help to unbalance the game the later you get.

Fifth: Come up with some other bonuses than a granary in each town, a barracks in each town, one extra happy face, two extra happy faces etc.
One idea would be to give the one who built the wonder one immediate bonus that lasts a while plus the possibility to research an unique tech that gives you a small edge in some area or to build cheaper or better buildings or units of some sort íf the wonder fits. Just as long as you don't get free buildings that either disappears or lasts forever.

Civs and cultural groups with many wonders may benefit from this but it's easy to balance in other ways, you could just see it as a cultural/religious trait.

It's all I can come up with at the time (not that all ideas are mine :p ), thoughts..?