Not all of our source is public so I doubt you can check that. :-)
Just one example where there could be a problem: filename pattern matching. We have customers that get news wires with odd filenames, and the pattern is user-configurable in the import module. It's the [ character that I think poses the biggest challenge, not the */? escaping.
It is also how glob works in other languages, such as perl python and go, if that is seens as more relevant.
I don't see how that justifies the incomaptible change. And this seems like a feature creep toward regexps, so it's not like it's been impossible to accomodate these needs already with a regexp.
Could it not be named Glob(), String.glob(), globx() or glob(a, b, 1)?
Another approach would be to claim glob(array, ...) as the extended syntax since it's only been available since 8.0, and the caller needing this for a single glob can arrayify the parameter easily.