The proper solution is, of course, to allow ←arrows→ (and, naturally, not trying to fit a variable peg into a monowidth whole)... maybe in the next generation of languages when the bottom level of typesetting quality is raised a bit
what would be ideal is a variable-width font which covers most Unicode characters consistently. some Unicode characters (eg, arrow) would need space of 2 characters and so on. making it elegant would require quite a lot of work to ensure Unicode does't look out of place (eg, arrow in your comment).
these are the problems which make me feel full Unicode editing is difficult to achieve in the short run. not to mention the obvious issue of typing Unicode characters from the ASCII keyboard.
i've included a reasonable subset of Unicode in Myna but it may not look very good. don't get me wrong, i appreciate the Unicode advocacy. but until we've something good-looking and well-behaving tooling on that side, using it would be quite frustrating.
I think the main problem with it is you need to use tabs for indentation and unfortunately spaces comprehensively won that battle. IMO that's because although tabs are clearly better, spaces are definitely more idiot-friendly and there are a lot of idiots in the world - or at least people who don't give a shit about nice formatting. So large tab based codebases tended to end up with a horrible mix of tabs and spaces.