Custom og:image for individual assets

I'd be interested in knowing who else would find it useful to be able to upload a custom og:image (aka Facebook share image) at an asset level — rather than just having Blox select the first attached child preview as the og:image.

We have found a few situations where we think we could get a better reaction online if we were to do a "text on image" sort of social image with our postings. However, attaching an image like that would look horrible on the front-end display in Blox, where we'd want the real child image (or no image at all) to show up.

Anybody else think this'd be useful?