That I absolutely agree with, but I think it is about time we let go of “programs as plain text” axiom. With good tooling/IDE — which are already sort of visual editors only converting to and from to plain text on save — you could enter a ‘+’ and get autocomplete show the “emoji +” as an option for example. Because the actually important question to ask here in my opinion is “what is the easiest way to read/comprehend programs”, and we seem to have implicitly agreed that syntax highlighting is already a must (which works on even not yet valid program text!). Slightly more reliance on tooling doesn’t seem too bad to me.
With a proper keyboard layout, you can type a lot of unicode: https://michaelgoerz.net/notes/the-us-international-scientif...
This might be a bit old school but I prefer things limited to plain ASCII. There's only so many keys on a keyboard and want to be able to touch type everything without thinking or looking at a special emoji bar.