A few years ago I thought about what it would take to implement a more conventional desktop GUI on top of Plan 9, but I’ve oscillated back and forth between wanting Plan 9 with a Mac-like desktop versus wanting a modern Lisp/Smalltalk machine (with object-oriented underpinnings instead of Plan 9’s “everything is a file” interfaces) with a Mac-like desktop.
Alef => Limbo => Go.
Being able to backport Go into Plan 9, doesn't make sense in this context, that isn't how historical evolution works.
Also even Inferno has the necessary C infrastructure to port Go, if someone hasn't done it already.
Though I do know that it puts some strong emphasis on mouse usage, something that for someone that grew to use the keyboard a lot like me (ironically, as a graphic designer) seems to be really awkward, to say the less. Its strengths seem to be its overlaying concepts and that it intended to be "the next gen Unix" - alas it won't take over for a myriad of reasons, and some would argue Unix-es have already borrowed some of its concepts for themselves.
(That said, there may have been an X server brought in at some point, but don't quote me on that. That's the least of anyone's problems in undertaking a CDE port though.)
Of course lots of it might be skill issue.