I suppose my original post wasn't complicated enough.
I'm fine with the peak/center temperature of the disc being 89 billion zillion Kelvin - black holes in SE do that just fine and I have no beef. The problem is that the disc (at default exposure) is homogeneous white all the way out to the edge ...

lol
Reminds me of a poorly translated instruction pamphlet I read once that said "Remember, the hardness affect protection, the thickness affect sensitivity."

...It was for a cell phone screen protector xD

IMO those discs are a bit excessively bright. I get that the center should be really hot and luminous, but when it's blinding white all the way out to the edge it looks wrong somehow. If it needs to be that hot at that distance for realism then the white dwarf discs should be made to extend farther ...

whoever designed Space Engine
That would be forum user "SpaceEngineer" ;) Welcome to the forum btw!
Note that galactic cores have a much higher star density than the periphery, as you can see looking around in space and also in the "Stars Found" area of the Star Browser. Within a given distance ...

I accidentally found Starkiller Base once xD
http://i.imgur.com/URFfQ0sl.jpg
More precisely, I found a planet that looked enough like Starkiller Base in the thumbnail to make me do a double-take. Up close, though, it can be seen that it's really just a regular planet with fairly large ice caps ...

I'm pleased to see that not only was the Kugelblitz Challenge not a trick question (i.e. neither works and I was too dumb to figure out why) but that I successfully determined which one it was. I couldn't be arsed to draw a Penrose diagram about it, though, so I never did submit an answer. I just ...

Oh. Neat idea, albeit somewhat more complicated.

Re-reading number 8, it seems like SpaceEngineer had originally thought up a torchship-esque design with parallel decks but later warmed up to the idea of radial decks with centrifugal artificial gravity, which happen to be what the Editor program ...

See that makes sense, but in the OP there's a bit about how the ship is designed like a skyscraper with cabins oriented along the axis of thrust, which wouldn't be useful if the ship only spent a fraction of the time generating artificial gravity using the main engines.

As long as the thread's already been bumped, I'm curious to know how much, if at all, the mothership concept has changed by now and how the existing ship editor and its sample ships stack up against it.
For instance, reading through the specifications above it seems SpaceEngineer was imagining ...