As a side note, if \() syntax has advantages over $ interpolation, please implement it and let femtocleaner clean old code 
No reason to stop advancing the language when there is a robot to fix software.
Regarding the conclusion stated above, it seems that both sides have strong opinions on the subject. It would be great to bring more people into the discussion before a decision is made? A healthy way forward is to open an issue on GitHub and invite more people involved with string processing to take a look.
Putting myself in the position of @ScottPJones, I wouldn’t appreciate a decision taken without careful discussion with all other members. Specially if it is about a subject that I have expertise on.