First of all, yes I do understand this is just a game and everything within it is very simplified and approximated.
Issue A, sizes. Yes, I do understand it is impossible to sustain real scale, and all the distances and sizes are very conditional, but all of the celestial bodies have different sizes, peculiar hint for players to understand which objects are bigger than other. But that system have some defects.
Examples:
Achaman. Good white dwarf relative size example.
Arcadia. Acceptable white dwarf size example.
Hybrasyl. White dwarfs can not be that big, it's compared to red and orange stars. Same problem with Zagan and randomly generated white dwarfs.
And, yeah, randomly generated brown dwarfs shouldn't be that big either. Real stars of that type are no much bigger than gas giants. But this is minor issue compared to that white dwarfs on steroids.
Issue B. Damn orbital mechanic. No, I will not whine about elliptic orbits, inclinations and Kepler laws. No.
Black hole orbiting brown dwarf. That sequence of words makes the hair on the back of my head stirring.
And it is kind of common to have smaller stars in a center of a binary systems.