I think one possible complaint you might get in the review is that when refreshing is fully disabled in the menu, people won't see new networks come up (e.g. when they had just enabled Wifi, or unsuspended).

Maybe a good solution would be to to have one unclickable menu entry pop up labelled e.g. "Networks changed, re-open this menu" to solve that. Probably in nm-applet's main context menu of which the list is a child, instead of in the list itself, so that its appearance doesn't move around the networks on which the user is currently intending to click.