I've still yet to see a noticeable difference between the display on the 4S and the 5. The 44% contrast increase doesn't come close to the bump from 200:1 to 800:1 we saw earlier. This is the first time since the iPhone 3G where a new phone wasn't given hardware-specific software. The 3GS had Voice Control, iPhone 4 had iMovie, and the iPhone 4S had Siri.
Well, the iPhone 5 has the ability to take pictures while shooting a movie, which I find particularly great.
But to tie specific software to specific hardware, unless by
pure limitations, it's never a good practice and I'm glad to see it going away, as phones get plenty of processing power and other hardware capabilities, just like what happens on computers.
I remember having a 3GS jailbroken while I waited for the 4, it was just a matter of changing a plist and iMovie would install and run. Siri also runs quite well on the 4.
About the display, it's true, but the problem is that it was already so good. They really didn't need to touch that... but they pushed the boundaries anyway, which is awesome, and the same goes for the processing power. It's also the first time since the iPad that a new chip goes to the iPhone first.