I think there still is the terrain/scenery generation process which is the bottleneck here - some of the airliner/VA folks actually stopped using the built-in navdb a while ago and are instead using online web APIs to retrieve the nav data on demand, a while ago someone else was also working on a Nasal parser to process the original X-Plane data files and use them for any MFDs.
It's actually a really simple format and easy enough to parse, most of this could even happen in a worker thread.
To be actually useful, you would obviously have to circumvent all navdb/navcache related API accesses and instead use your own wrappers.
But it's not exactly rocket science to do so - as a matter of fact, the MapStructure and NavDisplay efforts were designed with this in mind: you can basically replace all navdb API calls using a so called "driver hash".
Equally, it would be possible to write such a parser in Python and come up with a web service that can be used by VAs to always use the "latest & greatest", with all the pros & cons of not using the built-in navdb obviously...
The main APIs to be wrapped would be these:
http://wiki.flightgear.org/Navdata_cach ... _via_Nasal