I voted yes, as I have definitely hit the “you cannot use the same type of quote in the expression part” issue myself. And I think consistency in allowing whatever can be in an expression is easier to explain and understand.
Having said that, I’d prefer it if the PEP warned agains over-use of this feature, as it has the possibility of being difficult to read. In particular, I’m concerned about the possibility that formatters like black could try to enforce a particular style here, and I don’t think that would be a good idea (there are too many variables involved in deciding what’s “readable” in this context).