Seems kind of crowded to me. Particularly since this game has faster than light drives. My opinion is that most being with FTL capabilities will keep exploring to see what is over yonder.
So, I might make it a bit larger… say, 20 Traveller Sectors. Give the characters room to move around in. Neutron stars are a bit close. I think they should be further away. If one turned into a gamma ray burster, all would be lost. From the official map, nebula are rather close to. My maps will be unofficial.
The habitable zone for the Milky way galaxy inner zone is 7 to 9 kiloparsecs. About 23,000 to 29,000 light years.
Outer limit is 33,000 light years, this game is closer than Earth’s 28,000 light years out from the center, so I’ll place my Alternate Star Frontiers Universe ( ASFU ) at about 25,000 light years from galactic center, on the other side of the Milky Way Galaxy. There is a zone on the other side of our galaxy that is in a ‘shadow’ in that visual and radio telescopes cannot see much in that direction. That is mostly due to the dust and clouds between us, mostly hydrogen I think.
According to the Wikipedia article I read, the concern is the disruption of any solar system’s Oort Clouds due to being too close to the galactic center causing comets, and huge planets, to fall inward and wreck any inhabited areas.
It is here if you want to read it.
An excellent source of information is at Atomic Rockets.