We already have more galaxies, they just don't show up in the map and they are extremely buggy.Currently only the one galaxy, but honestly, do we need more? As for sector sizes, just change your sector size in the config to 5000 or do /sector_size 5000; apparently that's gonna be the new default.
Edit: Wait... 5000? I only ever play on 2000! Does this mean that we are getting more asteroids per sector now?