I'm honestly not convinced of this. I know it's gone terribly so far, but it's not clear to me that that's an interface issue and not an ecosystem problem with the phones in question. A menu bar, for instance, would certainly be unwieldy, but themed with large text it's no different than toolbars which certainly are found on mobile. It would frequently be clunky, but even limited support for the universe of existing software would in my opinion have a massive effect on the usability of any new platform.