1 - very important feature is to be able to Zoom in and Out in the Advanced Output panel. Sometimes I can't move the corners of a slice on the output window because they are too far from the screen window, they fall behind the parameters window for example,
if you resize the advanced output panel, the preview gets resized, but to fit.
for example if you make the panel large vertically you can grab points that are outside the Screen on top or bottom. that can be a workaround for now, until R5 has zoom.