Yeah, the killer is that the JPEGs that are embedded in the RAWs are only useful for a quick extract if you don't need to make any changes to the shot. Of course, that can be a big win, if you nail the WB, exposure, etc. when you snap it, so it may be worthwhile to keep storing Large/Fine JPEGs with your RAWs for just such occasions. You have to pay more attention to camera WB, etc., though, and you can't be as cavalier when you are just shooting RAW, if you want to benefit.
Otherwise, you are stuck with waiting through the conversion times to create JPEGs from the RAWs with whatever changes you've selected.
I found the FVU interface to be too slow and clumsy for running through a bunch of RAW shots. CaptureOne has a much better workflow for dealing with hundreds of photos. I can sort through a bunch of RAWs, make adjustments for white balance, exposure, etc. on them individually or in groups, and develop them to JPEGs/TIFFs in the background, and work on an additional batch of images, without having to wait for the processing to finish.