Recently I've resumed work on a font I'm currently developing, meant to be released as a completely free, open-source, OFL-licensed font designed specifically for use in papers, theses, books, lecture notes, and any kind of mathematics document more generally. It will consist of a family of fonts for text together with a family of fonts of matching style for math mode.
Since there are many typographical choices and specificities connected to mathematical practice, I wanted to ask for suggestions/wanted features from other mathematicians, in particular from those working in areas different from mine, which might have slightly different typographical needs which I'm not aware of.
As a concrete example of this, having support for letters from other alphabets used as math symbols is important in some areas, such as Ш for the Tate–Shafarevich group in arithmetic geometry, or よ for the Yoneda embedding in category theory.
A different kind of suggestion would be LaTeX specific optimisations or features for fonts which would be nice to have in practice, including e.g. a bigger set of delimiters, or built-in optimisation of microtype through a variable width axis (as e.g. discussed here), a feature relating to the text part of the font.
That said, in a vacuum a question like "Suggestions for features a math font should have" would arguably at best be a soft question, and at worst off-topic for MathOverflow. Nevertheless, given the free, open-source, nature of the font and the fact that ultimately it will be available to the broad mathematical community, I believe it would be reasonable to make an exception in this case, asking for input from the broad mathematical community as part of developing the font with the community in mind, and I believe MathOverflow would be a nice place for receiving this kind of input.
So―would it be okay to ask such a question in the main site? There I would define the exact gap the font is meant to fill, as well as give examples of the kind of input I'm looking for as an attempt to focus the question and define it a bit more clearly (although any input is going to be more than welcome)