My plans are to add several more string terminators. The current ideas are one for Bubblegum (base96, gzip, lzma), one for packed strings, one that interprets the string as a number and one that can be used to push arrays of small integers. Giving each a dedicated start and end terminator seems wasteful, given that this can save at most one byte in an entire program.
In related news, I'm working on a new compression method that never increases the size of printable ASCII. This would take `”` as a delimiter (so it can be omitted) and ultimately replace `»`.