Welcome to Camera Bits Forums
Seaking my way through a 1.500 RAW'S yesterday I missed the possibility to save them directly as RAW file (besides JPEG, TIFF and PSD). Perhaps not the first aim of PM, but it comes in handy sometimes.
Just to keep images in RAW- or DNG-mode untill editing later in Photoshop. Now I can save a selection from PM only as jpeg, tiff or psd, while I a would like to do that in the original format. Of course I can manage it in PS, but not as quick as in your program... Thats's why.
I would also definitely second this, as every caption I have at the end of it has copyright information, so the ability to add text to the beginning of the caption field would be a massive time saver.