I don't think anyone that writes regex would feel specially challenged by using the Alt+ | Ctrl+Shift+u key combos for unicode entry. Having to escape less things in a pattern would be nice.
I write regexes all the time, and I don't know if I would be CHALLENGED by that, but it would be annoying. Escaping things is trivial, and since you do it all the time it is not anything extra to learn. Having to remember bespoke keystrokes for each character is a lot more to learn.
Regexes are one case where I think it's already extremely unbalanced wrt being easy to write but hard to read. Using stuff like special Unicode chars for this would make them harder to write but easier to read, which sounds like a fair deal to me. In general, I'd say that regexes should take time and effort to write, just because it's oh-so-easy to write something that kinda sorta works but has massive footguns.
I would also imagine that, if this became the norm, IDEs would quickly standardize around common notation - probably actually based on existing regex symbols and escapes - to quickly input that, similar to TeX-like notation for inputting math. So if you're inside a regex literal, you'd type, say, \A, and the editor itself would automatically replace it with the Unicode sigil for beginning-of-string.
Regexes originate from Perl, or they were popularized by Perl if i got this right. In Perl readable code is not ranked as one of it's top 100 priorities. Regexes could originate from J and situation could be even worse though!
Regex's predate perl quite substantially. Think grep and friends if nothing else.
Certainly making the perlre library available separate to perl encouraged its widespread use, and lots of others copied or were inspired by it.
"Popularized" doesn't seem like quite the right word though, I don't disagree with the point, but if I shout "Hey everyone let's write regex's" at the office people throw stationary at me, which is not true of other popular things!
I took a look at Raku, which claims be a better Perl maybe, or closely related but more modern, it certainly looks nice. Although i am a big fan of typed languages, Raku piqued my interest.
ASCII restriction begets ASCII toothpick soup. Either lift that restriction or use balanced delimiters for strings in ASCII like backtick and single quote.
(“But backtick is annoying to type” said the Europeans.)
People say this all the time, but is it really always true? I have a ton of code that I wrote, that just works, and I never really look at it again, at least not with the level of inspection that requires parsing the regex in my head.
Even for code I wrote once and then never have to fix, I end up reading it multiple times while I create it and the lines around it. I think it really is always true.