I did a thread not too long ago on boosting crappy wonders and a very interesting idea came up: Swap Chichen Itza's bonus with the Great Wall's general bonus.
In other words, the Great Wall would now prevent all barbs from entering (which is the real bonus for most players) and a defence bonus in each city.
Chichen Itza, however, would now give a global (rather than domestic) +100% to GG emergence.
This would make CI a very viable wonder for warmongers, I think.
I think that would be a good balance improvement; but on the other hand, I think the Great Wall works pretty well as it is, and I don't really understand why CI should be useful for warmongers.
I don't see why Chicken Pizza should amplify great general points, or give additional city defence for that matter. I don't know much about CI, or history; but from what I understand the purpose of CI was to help produce food. It had nothing whatsoever to do with the military. From that point of view, it would probably make more sense for Chichen Itza to have the +1

bonus that the Hanging Gardens has. And then the Hanging Gardens would have to have something else instead, I'm not sure why the Hanging Gardens should help with health and growth anyway.
It's all a bit of a mess really. This discussion reminds me that "The Kremlin" in civ4 is actually St. Basil's Cathedral.
When making changes for K-Mod, I generally like to preserve the original flavour / strategy of the original game, which is why I was speculating about having an unbombardable 25% defence... but I am sometimes tempted to reshuffle a lot of these wonder bonuses so that they make more sense (to me).
Regarding the Space Elevator; I sometimes use it in K-Mod. (In K-Mod, it gives +100% rather than +50%.) When I use it, it's usually under conditions something like this:
I research computers to get the Internet, and then while I'm building the Internet I research Robotics to help bolster my defences (and because I'm sure I wouldn't get Robotics from the Internet.) The Internet then gives me Rocketry and Satellites, and so I can start building the Space Elevator and the Apollo Program at the same time. If I happen to get a Great Engineer around that time, I can use it to hurry the Space Elevator – which is effectively the only way the engineer can be used to speed up spaceship construction, since the spaceship components themselves can not be hurried.
So... when that kind of stuff happens, I don't think the Space Elevator is useless. But that's with double the bonus; and let me say again that I'm researching Robotics not for the elevator itself, but rather for the Mech. Inf., for defence.