They significantly changed the gradients in the header bars, toned down the pinstripes, updated the Share menus, made the navigation buttons flatter, totally redesigned the App Store and iPod, revamped the Weather app look, and themed the Camera as black. And much more. There is a slideshow out there somehow showing all the changes. It's definitely noticeable system-wide, and makes the OS feel more modern and refined.
A revamped messages would be much better too you know. A quick reply feature most of all like what bitesms can do since it is the only reason why i jailbreak and addint shortcut toggles on the notification will not hurt either. It's something I am not entirely happy about the iOS (don't get me wrong, i love my iphone and ios) but sometimes i find myself just constantly switching between 80 windows with in 2 seconds just to get everything up and working. Aside from that i am fine with the UI of iOS much less clutter and complicated than android and doesn't take much time to get used to.