The iPhone 4S can do everything (minus a couple of things the iphone5 can do). Thats the trade in price at Envirophone i think too, so seems like a good deal. I like my Iphone all-be-it i only use it for texting and few apps & surfing web.
The buggy bits funny as everything has bugs, and the last few updates worked across all platforms, so the 'new device to fix old' is rather funny.
Not to mention everything has to advance. By integrating features yearly, it makes users adapt and use them. Whereas if you were to update every 2-3 years, the amount of new features would cause head aches. All products do this, Samsung have already started talks about the S4. Even game consoles release 'updated models' like the Xbox with curved edges, or the Kinect ready xbox.. etc, isn't just an Apple thing, although people just get on a hate craze to iPhones as they didnt suit them.