The negative text is the impressive thing, and looks sexy on a finished board when it’s done well. I can perhaps justify the effort if the production run will go to thousands or tens of thousands, or if the board will spend much of its life “on display” on the desk or workbench. But many of us in the KiCAD world are doing prototypes, product feasibility demos, or small firms with production runs of a few hundred units. (If we were doing high-volume, long-run products we would be working for big companies that have spent big bucks on the big programs which integrate board layout with configuration control, MRP, etc.)
Is it practical to create a footprint library containing a pre-made, negative character, footprint for each character in a standard alphabet? (In the English-speaking Western world that’s around 50-ish footprints: 26 letters, 10 numerals, and a dozen punctuation or special symbols.) The character footprints can then be dropped onto a board similar to how we put mounting-hole footprints onto a board as needed.
We would have to agree on a usable size for the characters - perhaps 50 -100 mils (1.5 - 2.5 mm) high. This choice is constrained by the minimum copper width that can be routinely rendered by a typical board fab house (currently about 6 mils (0.15 mm)). And of course, it must be easy to embed the character footprints into a copper pour region so you get the desired effect of the negative characters!