The differences between iOS 6 and iOS7 are huge, there is a complete change in the User Interface. This is the biggest change ever done by Apple regarding its iOS where only new additions were added but this one is a complete overhaul. There is a change in the way the Apps looks, complete interface change and many New Features which were not present in iOS6.
Many people are saying that Apple has copied the design and features from Andorid and other OS but i must say it has done a great job at copying, who cares whether they copy or not in the end what matters is whether it is useful and loved by the users or not. It is not my company or yours so why fight for it.