this is a tricky request.
please consider how a larger display font size in the IPTC fields might be possible to make it easier to edit and read captions.
a foreseeable problem is that larger display fonts could make the floating windows ginormous. there doesn't seem to be an easy answer.
but the thought behind this request is to make it easier on the eyes when reading/writing captions in the IPTC fields and to help avoid mistakes in the captioning process because type is too small.
perhaps in preferences, end-users can set PM via a radio-button selection of two or three font sizes.
at this time, a continuously variable font size may not be as critical as having at least one larger display font size than currently available.
thank you for thinking about it.