Touch ID is innovative because it's the simplest/quickest/most-accurate implementation of fingerprint unlocking available so far on a handheld device. It's simply Apple looking at what's been done over the last decade and saying, "you're all doing it wrong."
HP's iPaqs, LG's feature phones, Toshiba's feature phones, Motorola Napoleon Q9n, Motorola Atrix, HTC One Max, etc., all use a bar sensor which require that the user swipe their finger across the sensor to get a full reading before it can authenticate.
Typically, this means that you'll need to do something to wake the device first, and then take a finger, and then swipe it across the sensor. Usually, these will be two actions in relatively different places on the phone.
It also means that as you swipe the finger, the amount of pressure you apply won't be consistent, and therefore can deform the reading inconsistently, resulting in read errors.
However in the case of the Atrix, the power button is part of the sensor, like the iPhone 5s. So you can unlock by pressing the sensor once, and then swiping. The problem is that people are tempted to press to unlock and swipe at the same time. This doesn't work well because the force uses to press the button isn't the same amount of force used throughout the scan. Therefore, it makes it even harder to read a fingerprint consistently. The reviews on the Atrix's fingerprint sensor have been overall negative, as owners in this forum have mentioned. One of my friends had one too. While he thought it was novel, did not continue to use it.
The iPhone 5s solves all these problems by letting the user combine both actions into one (wake and scan) and solves the accuracy problem by using a concave sensor that reads the whole finger at once. Pressure distortion is less of an issue as it applies evenly to the entire surface of the finger. Additionally, it can also read fingerprints from any orientation.
