While I suspect all the development effort at this time is focused on getting the ancestry merge working, some thoughts came to my mind in recent interactions on Ancestry.com that may be of interest as you enhance the Ancestry Interface.
I break my media into 3 classes, Documentation (images of census or certificates), family photos and individual photos. The documentation I would like to attach to sources, so I could print out the footnotes, but when interested, actually look at the relevant page.
RM does a pretty good job on individual photos, but it looks like Ancestry has a twist on that I'd like to see. When you attach a family photo to a person, you can select a portion of that photo as their profile photo. MyHeritage has a similar feature, when you click on "tag a photo", you can click on the photo where the face you want to tag is (much like tagging in facebook) and it draws a box around the click point. When you finish the dialog identifying the person, you can adjust the size of the box, so one family photo can provide multiple personal profile pictures.
If, after the Ancestry merge is complete, you can pick up their link data, that would be a neat feature.