Hardware:
Not much: that stupid camera bump (don't care if they make the phone thicker with empty space inside), and better screen to body ratio (iphones looked outdated even when iPhone 6 cameout), now it's just humorous compared to competition. The rest -- I'm extremely happy.
Software:
Just annoyances to be nerfed or option to disable:
1. Battery percentage notifications - arrrgggg! Don't care! I only care when it's at 1%-2% - still plenty of time to find a charger and plug it in, by the end of day, all I want to do is relax and play some afterpulse or RR3, and imagine in the heat of the battle or that s-curve inside the apex [20%, 10%, or 80% one: Your battery is sufficiently charged, the low power mode was turned off] - this is by far the MOST annoying thing every on iOS since day one.
2. Password requirement for Airplane mode or to Turn OFF device (Force Reset would need to be addressed somehow too). iOS is great at tracking your device, but the ability to just turn it OFF instantly makes it all moot if stolen.
3. Groups for Contacts: I'd like to separate my business from my personal (they can make tabs above)
4. If you select "Repeat Alerts" in Notifications for text messages, it should allow you to choose another tone for repeated notification, or make it sound different the second time. For example: lets say your text alert is "bleep" the repeated alert can be "be-blep", the third "be-be-bleep" - this can work with any native or custom tone.
5. Doesn't fall into iPhone or specifically iOS, but I need to design my own templates in Numbers App (iOS and iCloud).
6. I want an iOS native version of PhotoSync App: I know there's an iCloud Control Center, but the PhotoSync App does it so much better for us Windows PC users, in fact, latest update added ShareSheet access and now I can offload photos and videos directly from Camera Roll.
7. And this has been a big one since my first iPhone. When I create a folder in Photos and select a few photos to go into that folder - I WANT THEM TO DISAPPEAR FROM CAMERA ROLL!!!
8. Dynamic Weather app, but 3D touch kinda fixed that already, I'm happy enough.
9. Dark Mode - not a big deal at all, but I would love to see Apple UI team take iOS there.. Just to see how it would look.
10. Allow images to be seen in full (with black bars, or some blur effect, if they must) as background and lock screen images like they had before it was updated to force them to cover the whole screen. There's an app that does it for you, but why, just make an third option: Still, Perspective, and Fit. Also, more dynamic wallpapers or APK for 3rd-party devs, I know we can set live photos, but I want it to continuously be moving like the bubbles...
11. Small, but annoying: Everything on iOS is saved instantly when you change it, either in settings, in email, in contacts, in text, or in notes - I can start a new note, and close the app, but what I have changed stays. BUT, in Reminders app, when I start editing notes, or location, or time, I HAVE TO REMEMBER TO TAP "DONE" above, if I get distracted and comeback later, anything I typed is gone. I make location based reminders like a shopping list next time I'm passing HomeDepot - sometimes I don't finish right away, either to make a measurement or w/e and forget to tap "DONE" before exiting app - boom, the listed that's I stated in the Notes section of the reminder is GONE! I think it's an oversight by the iOS design team and I'm surprised it hasn't been addressed since inception.
I understand iOS 11 will address the following:
1. I loved how you can screenshot on Samsung Note and edit the thing right away, and share it instantly - been waiting for this, while using third party apps like Screenshot Edit.
2. I want to be able to draw on photos/images that you add in Native Notes App.
Now, a tons of things like above that "I" wanted over years of using iPhones and iOS has been satisfied: like always listening Siri, hiding native apps, always wanted something like control center (and it was better than I expected when it was introduced), iCloud Drive. 3D touch along solved a hundred annoyances by illuminating extra taps, and unnecessary UI.
Anyways, sorry for long post, it's been marinating for a while (as you can see)... sure hope someone in Apple sees my post.. They're actually little things that create big annoyances for me every day.
Great Topic.