Instead of doing an educated-guess of what to expect, here are three things I would love to see in iOS 10 (but have no expectation of seeing):
Folder Navigation Redesign
The navigation style of folders in iOS is frustrating: a 3x3 grid, which you have to swipe side-to-side to navigate if you have more than 9 apps in a single folder. At present, I have 219 apps on my phone (because I am a crazy person), so I have a lot of folders.
Folders should scroll vertically, while maintaining their central location in the screen. Scrolling up and down one-handed is easier than scrolling side-to-side when you're using a larger phone. In ergonomic terms, It just feels better.
Re-envision the Springboard
The iPhone homescreen hasn't changed much since iOS launched: it's still a basic grid of apps. Yes, there are folders, and yes, there are more rows of icons as the phones have been embiggened, but there have been no functional changes.
The onus is still on the user to dive into each and every individual app and take discrete actions. There is no usable, glanceable information in the form of homescreen widgets. There are widgets available in the "Today" tab of the notification curtain, but the bifurcation of the "Today" and "Notifications" tabs make the widgets kept there less useful. If you get a notification, you don't think to check the "Today" tab as well; again, the onus is on the user.
Windows may have lost the mobile OS era entirely, but they were onto something with LiveTiles. Interactive app icons would add incredible value to the homescreen.
Default App Choice, or, "Let Me Choose Default Apps for Crying Out Loud"
The fact that iOS is as sophisticated as it is and still doesn't allow for default apps choices at the system level is infuriating.
Apple has gone to incredible lengths to promote a robust app platform. But they undercut it by forcing users to use their own 1st party apps for things like mail, messaging, photos, podcasts, etc. I would much rather be able to set Inbox by Google, Camera+, and Overcast as my email/camera/podcast apps. The fact that Google and others have to use deep-linking and other tricks to workaround this severe limitation is a bit ridiculous at this stage.
When iOS 7 launched and all the skeuomorphic design elements were removed and replaced with flat and open designs, there was talk of how when the iPhone was initially released, analog comparisons still needed to be made in things like the calendar app, for the users' benefit. But by the time of iOS 7, we had all become acclimated to smartphones and no longer need those comparisons. We had matured as users.
Apple believes its iOS devices are the future of computing, but it hasn't reached a mature view of how people will want to use these devices in the way they envision. They want people to buy an iPad Pro as their primary computer, yet they have so far refused to let people change these basic settings. (This is the one single feature that makes me look oh-so-longingly at Android, year after year.) It's time that Apple trusted its users a bit more, and let them decide which apps they want to use to get things done.