Well, it's becoming harder to invent something "big" because the market is already littered with smartphone innovations. It's not like the old days of 2007 when smartphones were still fresh and simplistic, and Apple could "wow" the world with a simple touch-screen sensor.
Practically the only thing left for manufacturers, is to make small iterations to their current designs. Looking ahead, the iPhone 6 will likely be a small improvement over the iPhone 5s; with a faster processor, better camera UI, and an improved version of the operating system (iOS 8?). The same thing will goes for the Samsung and their Galaxy SV (whenever that's released).
I think boring years are ahead of us
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