Dvorak. Even after more than a decade, it's the only current OS I can think of that doesn't have a Dvorak option -- and the only Apple OS since the 1980's that didn't.
There are third-party keyboards, but none of them are good. That's not the third-party developers' fault: the iOS keyboard API is so wimpy, developers literally cannot make a keyboard that works like the default ones.
I don't want to hunt and peck, so on iOS I mostly use the Japanese "flick" keyboard, which is much more logical, but doesn't offer English autocompletion, so it's just bad in a different way.
I really don't know why iOS doesn't support Dvorak.
It works really well with any language that alternates vowels and consonants, which is most of them. I can also confirm it works great with Japanese, via Kotoeri (kana input essentially alternates vowels and consonants, even more so than English). I have yet to run across a language where it isn't better than QWERTY, though I'm sure they exist.
And less than 1 in 100,000 sounds awfully low. Where'd you get that number? There's 700,000 people living in my city and I personally know a lot more than 7 Dvorak users here.
iOS does support Dvorak for Bluetooth keyboards, so it's not so niche to cause Apple to ignore it completely. Isn't "Dvorak on BT (only)" even more niche than "Dvorak"?
This, so much. I've been a Dvorak-only user for nearly two decades, and the iPhone is unusable to me, as I'm not going to relearn QWERTY just for a single mobile OS.
Do any third-party keyboards on iOS even support Dvorak? Last time I checked, keyboards (e.g. SwiftKey) that support Dvorak on Android don't have the option on iOS for whatever reason.
I don't even need predictive text or autocorrect – just swapping the stock keyboard keys to Dvorak, and removing both prediction/autocorrect features would make it vastly more usable.
The especially infuriating thing is that iOS does support Dvorak at a software level – I use my iPad with an Apple Magic Keyboard via Bluetooth, and Dvorak works perfectly.
I share your complaints about 3rd party keyboards in iOS, but just a heads up in case you hadn't noticed: Google's Gboard recently added support for Dvorak and Colemak, and is by far the most stable/usable 3rd party keyboard I've used.
Multiple languages supported in the same keyboard. I frequently type in several different languages, and apps (and even contexts inside apps) never retain the correct keyboard for long.
The best alternative I've found so far is SwiftKey which lets you add dictionaries for many languages and just combines all of them together with Markov chains. Works perfectly. On the other hand, I miss out on features such as the new password filling, and I don't really trust SwiftKey privacy wise (they have a cloud service which they try to sell you).