I have learnt this lesson the hard way too - having 'evaluated' many applications in ignorance of the finer details of meta data storage. I have recently concluded that I am best served by keeping a master library of images as shot and having a working library to assign meta et. al.
The only correction I can think I would like to make to the master images is possibly a time shift due to forgetting to change the camera's time but right now I'm even sceptical about doing that - especially with RAW images. Phil - are you able to comment on whether or not exiftool can shift a time on, for example, a Nikon RAW image file (.NEF) without changing anything else in the meta? I seem to recall a thread where someone said that by default the date time info was stored in the Exif and IFD0 areas and yet exiftool only updates the Exif data - setting the IFD0 to null?