This is going to sound odd, but if Apple created an entirely new mobile OS not designed by Jony Ives, I would probably like it. I don't like the look of the menus which carried over from Mac OS, or the home screen which is and has always been pretty much a shrunken version of the Mac OS desktop. Take a look at the iPhone 1 and then compare it to an iPhone 6 - not much has actually changed regarding the fundamental look of the OS.
Even in 2007 I didn't really like iOS, but at least as far as multitouch smartphones, it was pretty much the only game in town. But even then I preferred Linux-based mobile OS' like Maemo, and devices like the
Nokia 770 Internet Tablet (2005) which was way ahead of its time.
The redeeming quality of iOS is that purely from an app platform standpoint it's perfectly fine. But I still hate the OS, don't like navigating around it, I hate the static home screen and icons, and the zooming animations and color scheme change of iOS 7 just made it a bad mix of old, Mac OS-derived and skeumorphic elements with the new flatter design. I especially hate the white and grey menus that still remain the default.
Windows Mobile had a similar problem with a legacy interface, which is why I'm glad it died, even though it was kind of "Android before there was Android" in the customization department. But the tiny touch targets designed for stylus clearly wasn't very good for touch, besides how clunky and buggy the OS overall was. Windows Phone, on the other hand, is fantastic for touch. And there is nary a holdover in the UI from the Windows desktop which preceded it (whether the "Metro"/"Modern" UI belongs on the desktop is a different story, and is being partly addressed with Windows 9, anyway).
Android, too, is better than iOS, and like Linux it comes in so many customized flavors from different manufacturers that there's one you are almost guaranteed to like, if you don't like "vanilla" AOSP Android. For instance, I love HTC's Sense UI. Others like the look of the various custom launchers. On iOS you still can't change the underlying look and feel of the OS, except for the recent introduction of custom keyboards.
The fact that they took so long to introduce just that feature, though, is precisely why I think iOS will end up like Mac OS: successful enough, but only controlling maybe 5 to 15% of the market share, and always behind on flexibility. Apple can make decent hardware and software, but personally I've always preferred its competition. The iPhone 6 isn't going to kill Android flagships, and I doubt the iPhone 7 will, either. At this point they are playing catchup, and Google is more than capable in making advances with material design, the speed and fluidity of Android, and a ton of interesting features in each new version. Right around Jelly Bean is when I think Android became dominant, and Apple really hasn't done anything to spell Android's imminent doom since then.