The GUI stuff was really my slightly facetious rejection of those people who complain about how inelegent web programming is, and how it should be more like GUI programming. I think they are just opening a can of worms for themselves, by trying to impose a style of programming they are familiar with to a domain where it is not appropriate. Of course, I also think GUI programming is a bit retro all considered -- I genuinely think that as a user, not just as a programmer. But that only directs my interest, it doesn't really effect the language much one way or the other.
Some of these aren't language extensions per se, but just hard implementation problems: microprocesses are an example of that, as is interpreter startup. I am hopeful that PyPy will open up this kind of development.