The latest public word I’m aware of is that Matt said the G3X wasn’t planned. That could mean MS intend to ditch it, or it could mean they haven’t officially contracted Working Title to update that one as of yet.
I suspect the latter because more 3rd party planes are now appearing using the G3X. They can’t replace the full nav system in the sim if the old G3X is still in place using it. So either it needs to be updated, or removed. And since several 3rd party planes have started using the G3X (SWS in particular) and several of the default planes use it, I can’t see them pulling the rug out from under them and removing it.
But as of right now, at least in the public sphere, it’s “not planned”. So I’m guessing at best it’s low priority and we shouldn’t expect to see if (if it happens) before AAU 3.