This would actually be really, really cool because it would allow creation of custom galaxies with a little bit of SQL wizardry to replace the randomly-generated JP network with a set of pre-defined JPs. For example with Real Stars, defining a JP network to connect all the stars in a constellation. The best thing would be that once implemented this would probably allow such custom galaxies to be transferable between DB versions using a SQL wrapper of some sort.
You can already pre-create the JP network with SQL wizardry if you like.
One challenge is determining the distance of each JP from the primary star. When randomly generated, this distance is scaled by the mass of the star. If you are pre-generating JPs, that mass won't be known.
You can overcome that with more SQL wizardry. Just write a trigger to update the JP locations whenever a new system is generated.
There's two big differences with this approach. First, you can define the JP network without creating every single system, which not only makes the SQL wizardry much easier (you don't need to go click "Create New System" 1000 times) but means that each game played on the same "map" can be different due to random system generation, allowing flavorful galaxies with replayability rather than always knowing for instance that you need to beeline through X, Y, and Z systems to get to Delta Fullofduraniumi before anyone else does. Plus random generation of NPRs, precursors, etc... basically start up a new game with all of your preferred settings and then run a SQL wrapper to generate the JP network.
Second, it would make it portable between different game versions, so that a JP network created in 1.14 can be played in 1.15+. Presently I think the lack of forward compatibility is a big restriction for people who want to create scenarios, anything larger than a few dozen systems is prohibitive in time requirement and by the time it was finished and released the new version will have come out and no one will want to play an out-of-date scenario. Obviously a JP network is only one part of a scenario, but it would allow for at least creating cool galaxy maps that can be replayed with minimal hassle.