Many people asked why Apple chose to implement this new Lightning dock in iPhone 5 and he did not opt for the much more famous micro-USB since he had promised to do so. Well, an engineer explains very simply the important reasons on the basis of which Apple took the decision to "revolutionize" the industry of coenctors for mobile terminals. The micro-USB standard would not be "smart" enough to be used by iDevices, and this is because it would not allow the terminals to work properly with Apple docks and other compatible accessories.
People keep asking why Apple didn't opt for the micro-USB connector. The answer is simple: that connector isn't smart enough. It has only 5 pins: +5V, Ground, 2 digital data pins, and a sense pin, so most of the dock connector functions wouldn't work – only charging and syncing would. Also, the pins are so small that no current plug/connector manufacturer allows the 2A needed for iPad charging.
The micro-USB ports have only 5 pins: +5V, grounding, two "digital" pins and a sense pin, and the Apple connector has 3 more that it uses to interact with docks and other compatible accessories. Using the micro-USB standard, Apple would have made many products incompatible with its terminals, but that's not all. The micro-USB standard has pins so small that no cable can provide the 2A needed to charge the iPad tablet, and without it Apple cannot fragment the charging/synchronizing system of iDevices.
More detailed explanations you have here, but you can see the summary above.
