The biggest point of complexity, IMO, is the representation in which the characters to be matched are mixed in with the syntactical elements in a single string.

This tends to cause confusion, makes escaping complex, and is just really different from most other ways of expressing logic in programming.

Even advanced regex features like extended mode and named captures, which I love, don't get around this fundamental issue with the representation.

It does have advantages though, a big one being terseness, and the ability to be expressed in an implementation-independent way. Another is that for some types of regexes, the expression "sort of looks like" the strings it can match against, which can help intuition.

I think the way forward is to consider the existing syntax a "terse mode" and to use regex builder libraries [0] as a "verbose mode." The "terse mode" does have merits, though, and I wouldn't want to get rid of it or anything.

[0]: For example https://github.com/VerbalExpressions/JSVerbalExpressions is a library that lets developers express regexps using a fluent API. This changes things from being syntactic elements of a string to just being traditional function calls.