Every time I have to build a GUI in Linux I just build a webapp that connects to a TCP backend on localhost because that way I can just build a beautiful UI in HTML/JS/CSS and I don't have to deal with the mess that is GTK, QT, TCL, TK, and all that crap.
Android programming is another can of worms and I'm frankly fed up with Gradle updates breaking my project every update and needing 79+ files, multiple cludgy steps for signing APKs, zipalign (wtf) and other crap just for a Hello World.
What would be nice to have is "installable" apps that use the webkit rendering engine but have full access to the system including directly opening TCP ports and direct access to /dev. These would have to be trusted apps obviously. Websites that load code without consent should be restricted, of course.