Using that mass requirement means brown dwarfs and similar objects are now very important, so important that there's going to be a lot of effort dedicated to detecting and charting them.
You'll have publicly known objects and privately known objects with governments, organizations, corporations, and individuals all busy looking for others and charting shortcuts. The setting's "scouts", government or private, will be in great demand.
Stealing coordinates and other such survey data will be part of the picture too. Before sea-going clocks made fixing longitude simple, navigators used "rutters". Stealing or copying those rutters was a constant occupation for governments, companies, and individuals. Updating "public" rutters was a constant occupation too.
Then there's trade wars angle (along with old fashioned wars too). Imagine a trading company which alone knows the location of the brown dwarf that cuts travel time between two systems by, 50%, 75%, or more. They'll keep the location secret, but their competitors will be able to deduce where to look and eventually located the object. When they try to use it, they discover the first company has warships stationed there.
It would be like the trade war adventure in TTA except around a brown dwarf and with Arekut attacking the interlopers. Portugal did just that for a few centuries while surveying and using the Cape of Good Hope route to India. They developed the rutters, they kept things as secret as possible, and they tried to kill any Europeans they found south of the Gulf of Guinea.
Please do. I know I'm not the only one who would love to read it.
Some good points on the navigational issues - I hadn't even considered the possibility of "secret" jump points, but that is a great idea. Particularly as I can see the government(s) of the region exploiting them as you said. When combined with my other plan of each linkage has a particular point within the origin and target system, those "Star Rudders" would be worth their weight in platinum to the right people...