My general feature request for all font programs is:
A display more where the main pane is 99% just pure font previews.
In other words, what i find frustrating in most of these advanced programs is all the extra text they want to show me along with the font (underneath it or above it), including filename, etc.
The main thing i use these programs for is for choosing fonts. so for me what i want is a giant pane just showing font samples (preferably multi-column so i can pack more on a page), with no extra info in that panel but the line of sample text. Then if i click on a sample you can show me the file name etc in another pane.