This is not so much a "feature request" but a "requirement" (for practical applications). :-) Please note that I have only just started playing with Vuo and perhaps I'm missing something, apologies if so. Currently, all windows I create seem to be 1024x746, kind of amusing to me to imagine where those numbers came from, nothing standard.
What is required is to be able to control the aspect and/or resolution of a window. Since most presentations are going to be run full screen, only by the designer having control over the aspect can any graphics be located correctly within the normalised window coordinates. One can see this is a problem already by running many of the demos fullscreen on an HD display/projector ... they end up clipping top and bottom.