I have been working on MPD browsing performance and think it has been taken pretty far.
However I am still noticing that it takes quite a while for a browsing page with a lot of entries to show: 350 items takes approx 4 seconds to show on my Raspberry Pi 2).
When I look at the java script console in this situation I see that the websocket response is instantaneous but then the DOM takes approximately 4 seconds to build.
I therefore think it would be good if we could focus some attention on improving the rendering speed of the UI.
This would really make Volumio snappier.
This is in no way meant as a criticism of the UI, just a statement that if it was optimised a bit we might really start to see a nippy application.