In that case, that’s a big problem because it already doesn’t work for me on AnkiMobile 
(window.sendMessage2 in particular doesn’t seem to exist in AnkiMobile today at all)
Is this something that by nature is not easy to add because of Apple/iOS limitations?
Otherwise I don’t understand why iOS would be by design different from the others.
To be honest I’m a bit skeptical about this argument of confusing users. It is the responsability of people making / distributing decks publicly to explain what those decks are supposed to do to their audience.
Also, those hypothetical decks should already exist, because the functionality is already available on AnkiDroid and Desktop. Did you notice any surge in confused users? I mean, compared with regular Anki stuff… 
On my hand this is something that I want for personal use, I do not plan to publish anything. And not having these triggers accessible in Anki Mobile I must say is very frustrating — especially considering they are available on every other platforms. And from here those people just look like very happy people to me 
I believe those are really important missing features that limit Anki’s scope for the purpose of language study.
Time, and in particular study time is a very rare ressource especially as you get older. The only times when I can do these intensive language practice things is either : on the go (in transports for instance) or while doing chores with bluetooth headphones. Not in front of a computer.
For those reasons, would you please reconsider exposing these functionalities in AnkiMobile publicly? Many thanks in advance !