Reusers quite often attribute an image to the uploader instead of the author. One of the contributing factors to this can be the way the uploader and author are attributed in the MediaViewer: While author name is mentioned on the left side of the description, it is only marked by an icon and does not stand out particularly. The uploader, on the other hand, is part of the nicely formatted box on the right, just below the license information and is therefore more prominent.
I suggest to remove the uploader information from the MediaViewer. It is only a technicality that has no meaning to viewers and reusers. Its prominent mention is detrimental and has no legal reason. Contributors will use the old File page with its abundance of information anyway.