On the flip side..
.. that Keynote collaborative feature and Keynote live work amazingly well, despite the collab feature only being in beta. The only problem I have with the collab feature is that I am absolutely no fan of storing anything in iCloud, it's too much of a single point of failure for me, plus it's hosted in a nation where agencies are known to subvert providers (Yahoo being a recent example, I suspect that's just the proverbial tip of the Titanic destruction device).
I know it's traditional to moan and my years as auditor have shown that some people have an obsession with negativity (it's easy to point at what someone has done wrong, it's more challenging - and IMHO far more interesting - to come up with solutions in the same process), but I'm still quite happy with the combination of Linux and OSX/MacOS that we use. I would agree that iOS 10 doesn't feel like *much* of an improvement (the unlock ergonomics are IMHO a step in the wrong direction), but it did add some features that come in handy such as cut & paste between equipment and the ability to configure some OTP codes to appear on the lock screen if so desired (that's a combination of lock screen functionality and the OTP Auth app where you can choose what shows and what doesn't). That said, I had not noticed it had removed the time storage limit in email, but a check in airplane mode shows it actually only stores the headers until you scroll to a message, I can live with that.
If you want two longstanding problems that have not been addressed, look at Apple Mail and the Finder.
With Apple Mail, even the new shiny version is unable to distinguish between ATTACHING files as separate objects and EMBEDDING files like images in the message (and no, doing that "at the end of the message" is not the same as attaching). Why can Thunderbird and Outlook do it, but not Apple Mail? WTF?
The Finder, meanwhile still lacks the simplest of usability: it is unable to put folders first in a directory. No, really, I kid you not, there is NO way of placing folders first other than either giving them a special name or sorting on kind which cancels any other sorting you'd like.
There were external solutions for it (which basically meant we'd landed in Windows land again - fixing deficiencies that shouldn't be there in the first place), but it appears Apple has outengineered those since v 10.11 so now you can't solve those issues at all - issues that should have vanished YEARS ago. It's a good thing everything else works so well, but if you want to put a spike in an Apple fan's waffle about ergonomics, here you go - stuff you've been able to do in Windows pretty much from day one.