Well the thing that bothers me the most is that Unknown Regions take almost entire left half of the galaxy. And even more so that they span almost to the core.

I would not mind if the Unknown Regions would be at the edges of the galaxy (for example inside those arm ends) or even outside the ring. It does not make sense that a small distance to the left of Coruscant is completely undiscovered while 10 times that distance to the other side is known (such as Tatooine).

I mean I do not know know which EU author actually mapped the galaxy. I think he/she is the one to blame. Well it is true that Unknown Regions appeared in KOTOR game and other sources but they never determined its position and size.