Hi, I have three suggestions for the Reference View UI that Capture One provides, and I hope LR will also.
First, I should be able to use the Shift key to drill down into both images, and also, pan within both images, as long as I am holding down the Shift key. This lets me quickly compare two images for sharpness, micro contrast, color, etc. at different parts of an image.
Second, I should be able to click to select either image in situ and be able to edit it. I might be comparing two images from two different cameras, and I might like the way the greens were rendered in one and the magentas were rendered in the other, and neither image might have been perfect. So I ought to be able to tweak either image to bring it closer to the other. If the Reference image is a "gold standard" that should not be disturbed, then it is easy to provide an edit lock for that image. Currently, the only way I can edit the reference image on the left is by also making it the working image on the right, which is very cumbersome.
Third, as a follow up to the above, currently if I try to crop the Reference image, I get kicked out of the dual-image mode altogether. Frequently, I am trying to crop two images to the same size, by having the same margins around a subject in the center. I should be able to adjust the cropping on an image with a reference image on the left.
Hope this is useful feedback others will also find useful, and they can be implemented.