I very much agree with you, Chris. If it's built for photographers, photographers should be able to define which file types are part of their workflows.
However, I also agree with Jeff. I've put the need to Adobe many times, and I've seen no sign of any inclination to move from the line that file types must be camera-generated. The application of that policy may have shifted in the past, when photographers started shooting video, and it is inconsistent now that PNGs are also allowed, but Adobe's heels are well dug in. Second, while this improvement is largely about removing restrictions, not adding features, it's much more than a JDI. As a minimum you'd want to display the operating system thumbnails of other files, and you've got to move the restrictions on file types and prevent users putting Word or PDF invoices through Develop, for example.
The nearest you can get is a plugin called AnyFile. I don't know how well it works.