> Not everything makes sense to be in a left-to-right stack. The windows that pop up from the bottom are supposed to have a different purpose (usually have a "Close" button) vs the nav stack that have a back button
I agree. I think what I'm getting at with that is less about how you structure your app, and more about my frustration that there is no universal way of going back. If the developer forgets to implement a back button, suddenly I can get stuck on a step and having to restart the app. In a non-iOS app UI (like desktop GTK, browsers, Windows UI or anything really) it's always really obvious that I can press the OS hotkey to go back, or press backspace/escape to get back to where I was before.