I don't know if this is a LR topic or a topic that should go in another forum but...
After going out for a shoot on the weekend and coming back home to work on the images, I've realised that the reason for wanting to be able to do merging and so forth with raw image files is that when I bring the result back into LR, LR has no idea about what camera was used to create the image and thus doesn't know as much about how to correct it.
As a for example, when I import CR2s into LR, they've all got various defaults applied such as exposure of -0.66. If I then select a batch to ship out to PS for a panorama merge, the resulting TIFF that further I edit in LR has the exposure as "0". Why? Where does the information loss occur?