Oh, yes, if there's a way to signal a scroll attempt to the application then it's totally doable.
Is this the "Scroll alternate screen" checkbox? I believe that just controls the scroll wheel, and makes it not do native scrolling and instead just send a page-up or something. If so, then non-native scrolling is definitely possible ... but it's already possible if you run screen or tmux instead of mosh. (Which is what I do, and it works fine for me, in part because I learned how to use screen's scrollback even before mosh existed.) I can see the argument for exposing this with better keyboard shortcuts than screen's inscrutable ones, but my impression is that people mostly want native scrolling so they can, e.g., drag in the terminal UI to copy and paste a large amount of text. You can't do that with non-native scrollback, since the text isn't all contiguous in the terminal window.
Is this the "Scroll alternate screen" checkbox? I believe that just controls the scroll wheel, and makes it not do native scrolling and instead just send a page-up or something. If so, then non-native scrolling is definitely possible ... but it's already possible if you run screen or tmux instead of mosh. (Which is what I do, and it works fine for me, in part because I learned how to use screen's scrollback even before mosh existed.) I can see the argument for exposing this with better keyboard shortcuts than screen's inscrutable ones, but my impression is that people mostly want native scrolling so they can, e.g., drag in the terminal UI to copy and paste a large amount of text. You can't do that with non-native scrollback, since the text isn't all contiguous in the terminal window.