You can increase the font size of the application as a whole, but not AFAIK for the book details pane specifically. I did warn you above that it is currently not possible to control the order of columns displayed there.
As for feature requests for changes, the proper approach to request those is via the Calibre bug tracker.
https://bugs.launchpad.net/calibre
That you are asking for font size control is slightly different to my previous request so perhaps you may have more success in convincing Kovid.
