I highly doubt Apple will do anything too radical with iOS. It's still a enormous success for Apple. They might be loosing market share to Android, but they still earn a hell of a lot more money on iOS and their devices compared to any other in the industry.
Take a look at the Mac and OS X situation, it's never been about taking the entire market and only be satisfied if everyone loves you and use your devices. It's about offering the best ecosystem and integration across their own lineup, Apple want to be the very best at integrating their products and make life easy for the user.
One can always argue whether your MacBook is the best notebook purchase one can do, whether the iMac is the smartest desktop option, whether you'd might consider BoxeeBox or something else instead of the Apple TV, you might go Bluetooth instead of AirPlay and what not.
The thing with Apple is once you get used to the seamless integration between devices you get spoiled and going back to having a Android phone, combined with various Windows systems and a bluetooth speaker along with a WDTV Live in the living room and you have a whole mess on your hands and your family can barely understand how to operate any of it.
And the competition understands this, there is no real doubt about Microsoft and Google starting to jump the ball and go the same route as Apple in terms of seamless integration between devices, but after testing out Windows Phone 8 with Windows 8 and their tablet lineup and seeing how Google is going with the multitude of Android devices they are no way near Apple in terms of simplicity and seamless integration, at least not yet.
As long as Apple keep on doing what they are best at, keeping their system so tightly and seamlessly integrated with each other and keep on focusing on easy to use setups and devices that "just works" they will keep most of their extraordinary loyal customer base.
The biggest mistake Apple can make at this point is starting to change things just for the sake of it. If people suddenly have to re-learn all their iOS devices and they start altering the whole user interface experience they will start seeing some serious drop in their rather loyal user base. People whom want to flicker with settings and customization out of this world will always stick with more open source solutions compared to what Apple has to offer so don't start messing with your current customers in a hope for gaining some from your competitors whom chose the other platforms for a reason to begin with.
That said they could really step up their game in terms of evolving quite a few things, some of the stock applications are simply lacklustre and not remotely close to being up to 2013 standards. But again, Apple is saved by it's rock solid ecosystem as nobody barely uses any of the stock applications to begin with as you have such a awesome library of good third party applications.