I saw the idea for a push to live feature for OBS for on the fly editing without the stream seeing it (which is cool). Sorta similar, it would be nice if you could have preview enabled and smoothly transition to streaming without having to disable live preview first. I'd actually like to have preview enabled by default (so it's always on). Of course a option could be added to have it disabled, but I like seeing what's happening in a preview before I go live.