To be able to adjust exposure by dragging the histogram and having that sync across to all images that you have selected.
You can currently do this this but the + / - of the exposure (or shadows, highlights etc) is what syncs, not the histogram.
So, if you have multiple images selected, and adjust the histgram on one image, and that therefore translates to a +1.50 of exposure, then all the selected images are also adjusted by +1.50 of exposure.
This can be the same for shadows, highlights etc but each image would therefore have differing histograms.
It would be handy to be able to sync the images by histogram, so each image selected could therefore be differing figures on the sliders (eg +1.50 for one, +0.75 for another etc - but the histogram reads the same)
Great for getting a batch of images synced if you happen to be over / under exposed when shooting.
I shoot a lot of sport and this would be much quicker to batch process images for a match.
Hope that makes sense.