There are a lot of differences between the 4S and 5.
The 5 comes with a brand new, 4" retina display. It comes with a brand new A6 chip, twice as fast as the iPhone 4S. It comes with an upgraded camera, it uses a sapphire crystal lens. The front facing camera is also 1.3MP. It also comes with LTE. It's thinner and lighter. The back is an aluminum and glass mix instead of all glass. The headphone jack is at the bottom and instead of the 30 pin dock connector, it is a lightning connector now, it's smaller.
I think it's possible that it makes the purple haze worse. I haven't researched this, but I've been wondering what hardware in the iPhone 5 makes the purple haze effect more dramatic than it is in the older iPhones. I initially thought it might have been a side effect of the better low-light capabilities, but the lens cover being the culprit is plausible. It's pretty much a non-issue for me since I don't take pictures of bright lights, so I haven't bothered spending much time looking into it.