The GUI is trivial. If there is a cross-platform backend, writing a GUI will be just a matter of several days.
Trivial, hah, I thought the same in the first two weeks of working on this, when I had made some mockups in Qt Designer. Then reality hit me.I think John Smith did a feat of software engineering comparable to doing a successful face ansplant on a Frankenstein.
You have to start somewhere uh 
Have many face transplants have you done where the patient was trying to strangle you 
Which is also why I'm done bickering about whether Qt was the right choice, why not the zillion other UI libraries, why I chose this specific URL scheme etc. If you have anything to add, you know where the "pull request" button is.
I've implemented the most-requested features and removed the most common annoyances, and the UI as a major concern is now addressed.
Now let's move on to helping Alex Waters with his QA stuff so that we can refactor the core code *with* the assurance of unit tests.