Yeah, it's a shame Qt/C++ doesn't have any way of interacting with USB devices and there's no libraries for that, otherwise there could be a native GUI app for QMK. Or failing that, because Qt is simply too difficult for programmers to figure out, maybe some day there will be a way to deal with USB devices from Java, then at least we could have an AWT app (or I guess Swing is the new hotness now?).