Great request - especially on more complex projects where the files need to have a similar name and are long. When You have a lot of long named files the "hover & reveal" method is a pain.
If for some reason this is a problem for the UI - how about truncating the name after so many letters to allow for the last several characters to be viewed? (Like the Mac OS does now but with a few more end characters visible.)
Truncated name in Resource panel: