I get why programming languages stick to plain text files, but I kind of wish there were more options. I want to insert mathematical expressions and have them look like they do in a math book. There is LaTeX but a C compiler can't parse that, and it's not very WYSIWYG.
What I'd ideally want is to have the whole stack (keyboards, editors, source code files, compilers) be adapted for it.
Also, variable names with greek letters and subscripts would be helpful.