This year Apple gave *a lot of love* to iPads: we're all in awe for how well they've implemented drag and drop, and I'm personally even happier for system-wide markup.
The new iPad Pro 10.5" is probably the best incarnation of the most versatile tablet form factor, and the combination of a Dock and an app switcher that both feel very Mac-like and platform native at the same time made this WWDC one of the best Apple events ever for iPad users.
There is one thing, though, that iOS still misses, and it's something the operating system always had under the hood: the ability to allow multiple users to use the same device with a separate environment, giving each person in a family access to her own data, apps and settings. They made something last year for education, but it was pretty limited in scope and a bit different from regular users' needs.
I am not saying that adopting multiple logins would be an easy feat for Apple, nor that it would be viable on all devices: since iOS apps save data inside their own app containers, I guess it would be a serious challenge for Apple engineers and app developers, and many devices haven't enough disk space to allow the comfortable coexistence of different people on one device. The list of problems wouldn't stop there: Touch ID would certainly be a requirement for quick user switching, inter-user document sharing would soon emerge as a need... the list of challenges would be long indeed.
Maybe more important than the technical reasons, which I believe Apple would be able to overcome in a reasonable amount of time if they decided to put their technical resources at work, I've read in the past that our favorite fruit company would never allow multiple users on the same iOS device, since iPhone and iPads are very personal appliances, and it's also good for business to have each family member to buy a separate one. This is an argument I don't buy: while it actually makes perfect sense for every person who can afford it to have a personal smartphone, for many households a tablet covers completely different needs, and actually most families can get by with just one iPad, and they are doing it right now.
I actually believe allowing multiple users on iPads would be great business for Apple, given how many old tablets are still around since they are already so good people don't see the need to update: make iOS 12 accept multiple users just on iPad Pros (they started at 32 gigs from the beginning and all have Touch ID and a lot of processing power), and you'll give families the most compelling reason to buy a much more expensive device (the 10.5" Pro costs almost twice as much as the new iPad, which by the way is almost too good for that price point, posing a challenge right there for Apple revenue, since it could be very tempting for most users to renounce Pencil support and some other advanced features in order to spend significantly less money).
This ship has sailed for iOS 11, but the silver lining is that now Apple has almost a year to make it happen the right way, just like they did with drag and drop.