Like T145246: Provide some more room for search results in the gallery dialog, this might also be solvable with T64677: VisualEditor: Merge the media editing and gallery editing dialogs.
When I select images for a gallery, I can't see, much less copy, the image descriptions. Or the complete file names. Or open the images in another tab. This makes it difficult to select the correct image in some cases, and impossible to write accurate captions in others. I want to see and to be able to copy the kind of information that the Media dialog gives me, or at least to be able to open the regular File: description page in another tab.