Back when IOS 7 came out Apple changed a lot of things that we all knew and loved they added a new app switcher and whole new UI. But some people (my self included liked the way that IOS 6 looked. So i Apple put a option in the settings of IOS 10 you will have a lot of people who loved that look come back. Something like this should not be to hard to do and now before IOS 10 is released would be the perfect time to do this. I think that you would see a much higher rate in people that upgrade to IOS 10 from IOS 9 and even IOS 8. Bring back the classic look of IOS. Also as you can see the overall look for IOS has not changed that much from IOS 7 to 9. I don't want it to be strictly IOS 6 I just want a choice. (Thanks to EverythingApplePro for pic).