>>wicket+(OP)
While I share the concerns about Android, it feels silly to me to go back to Linux's (nonexistent) security model and bad mobile UI/UX. Why not try to fork AOSP or GOS (for broader device compatibility, even if it means giving up some its sexy security properties)?
Note that this could include packaging Linux GUI applications as Android APKs (with some additional glue code and Wayland/DBus integration of course), so it's not even an either or.