One of the main detractors that stops me from using the network render option more (besides a serious unresolved bug
viewtopic.php?f=72&t=33853&hilit=+network ) is the fact that you have to manually ask for a preview and when you do, it takes quite awhile to get.
It would be nice to have a built-in preview window, even if it were just the size of the normal render preview. It could even just use the host computers render to preview rather than having to continually merge renders to generate a preview.
-Brodie