I would nice to have, in addition to the histogram, to have the ability to show over exposed and under exposed areas. Nikon capture, for instance, does this with a press of "L" or "S" (light or shadows) which toggles them on or off. This can be useful when sorting bracketed images. The Histogram does not show this well when the over/under exposed areas are very small. I have to go to the editing program to check this now, a bother.
The other feature would be a true full screen preview (similar to Corel Paintshop pro) that shows the image on a black background without any headers or title bars. The Photo Mechanic "full" screen preview is distracting because it shows the top title bar and the tool bar as well. The true full screen mode should probably be in addition to this, perhaps as a function key or whatever. You could also consider a simple "Slide show mode" that would sequence through the images.
Renaming would be easier if the textbox would default to show the original file name rather than being empty, so that you don't have to retype the whole name if you want to just add a suffix (e.g., renaming mylongfileName1.jpg TO mylongfilename1-A.jpg).
